feat: add GitHub Actions workflow for building and releasing uzdb across Windows, macOS, and Linux

feat: implement NewConnectionDialog component for creating and editing database connections with form validation

chore: generate TypeScript definitions and JavaScript bindings for app functions

chore: add models for configuration, connection requests, and database entities

.github/workflows/release.yml

@@ -0,0 +1,137 @@
+name: Build and Release
+
+on:
+  push:
+    tags:
+    - 'v[0-9]+.[0-9]+.[0-9]+'
+
+permissions:
+  contents: write
+
+jobs:
+  build-windows:
+    name: Build Windows (amd64)
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.25'
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '20'
+
+    - name: Install Wails
+      run: go install github.com/wailsapp/wails/v2/cmd/wails@latest
+
+    - name: Build
+      run: wails build -platform windows/amd64 -ldflags "-X main.version=${{ github.ref_name }}"
+
+    - name: Package
+      run: |
+        cd build/bin
+        Compress-Archive -Path uzdb.exe -DestinationPath uzdb-${{ github.ref_name }}-windows-amd64.zip
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: uzdb-windows-amd64
+        path: build/bin/uzdb-${{ github.ref_name }}-windows-amd64.zip
+
+  build-macos:
+    name: Build macOS (arm64)
+    runs-on: macos-15
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.25'
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '20'
+
+    - name: Install Wails
+      run: go install github.com/wailsapp/wails/v2/cmd/wails@latest
+
+    - name: Build
+      run: wails build -platform darwin/arm64 -ldflags "-X main.version=${{ github.ref_name }}"
+
+    - name: Package
+      run: |
+        cd build/bin
+        zip -r uzdb-${{ github.ref_name }}-darwin-arm64.zip uzdb.app
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: uzdb-macos-arm64
+        path: build/bin/uzdb-${{ github.ref_name }}-darwin-arm64.zip
+
+  build-linux:
+    name: Build Linux (amd64)
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.25'
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '20'
+
+    - name: Install system dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y \
+          libgtk-3-dev \
+          libwebkit2gtk-4.1-dev \
+          libayatana-appindicator3-dev
+
+    - name: Install Wails
+      run: go install github.com/wailsapp/wails/v2/cmd/wails@latest
+
+    - name: Build
+      run: wails build -platform linux/amd64 -ldflags "-X main.version=${{ github.ref_name }}"
+
+    - name: Package
+      run: |
+        cd build/bin
+        tar -czf uzdb-${{ github.ref_name }}-linux-amd64.tar.gz uzdb
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: uzdb-linux-amd64
+        path: build/bin/uzdb-${{ github.ref_name }}-linux-amd64.tar.gz
+
+  release:
+    name: Create GitHub Release
+    needs: [ build-windows, build-macos, build-linux ]
+    runs-on: ubuntu-latest
+    steps:
+    - name: Download all artifacts
+      uses: actions/download-artifact@v4
+      with:
+        path: dist
+        merge-multiple: true
+
+    - name: Create release
+      uses: softprops/action-gh-release@v2
+      with:
+        name: uzdb ${{ github.ref_name }}
+        draft: false
+        prerelease: false
+        generate_release_notes: true
+        files: dist/*

frontend/src/App.css

@@ -13,7 +13,7 @@
 .view-tabs {
   display: flex;
   gap: var(--space-1);
-  padding: var(--space-2) var(--space-4) 0;
+  padding: var(--space-3) var(--space-4) 0;
   background-color: var(--bg-primary);
   border-bottom: 1px solid var(--border);
   flex-shrink: 0;
@@ -23,8 +23,8 @@
   display: flex;
   align-items: center;
   gap: var(--space-2);
-  padding: var(--space-2) var(--space-4);
+  padding: var(--space-3) var(--space-5);
-  font-size: var(--text-sm);
+  font-size: var(--text-base);
   font-family: var(--font-sans);
   color: var(--text-secondary);
   background: transparent;
@@ -83,6 +83,33 @@
   outline-offset: 2px;
 }
 
+/* DataGrid empty state (no table selected) */
+.datagrid-empty-state {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  height: 100%;
+  gap: var(--space-3);
+  color: var(--text-muted);
+}
+
+.datagrid-empty-icon {
+  font-size: 40px;
+  line-height: 1;
+}
+
+.datagrid-empty-state p {
+  margin: 0;
+  font-size: var(--text-base);
+  font-weight: 600;
+  color: var(--text-secondary);
+}
+
+.datagrid-empty-state span {
+  font-size: var(--text-sm);
+}
+
 /* Selection color */
 ::selection {
   background-color: rgba(59, 130, 246, 0.2);
@@ -91,6 +118,7 @@
 
 /* Print styles */
 @media print {
+
   .view-tabs,
   .layout-menubar,
   .layout-toolbar,

frontend/src/App.tsx

@@ -4,40 +4,61 @@
  * Main application component integrating all UI components.
  */
 
-import { useState, useCallback } from 'react';
+import { useState, useCallback, useEffect } from 'react';
 import './index.css';
+import './App.css';
+
+// Wails bindings
+import {
+  GetConnections,
+  CreateConnection,
+  UpdateConnection,
+  DeleteConnection,
+  TestConnection,
+  GetTables,
+  GetTableData,
+  GetTableStructure,
+  ExecuteQuery as WailsExecuteQuery,
+  DisconnectConnection,
+} from '../wailsjs/go/app/App';
+import { models } from '../wailsjs/go/models';
 
 // Import components
 import AppLayout from './components/Layout/AppLayout';
-import MenuBar from './components/MenuBar/MenuBar';
 import ToolBar from './components/Layout/ToolBar';
-import StatusBar from './components/Layout/StatusBar';
+import ConnectionPanel, { DatabaseConnection, Schema, Table } from './components/Sidebar/ConnectionPanel';
-import ConnectionPanel, { DatabaseConnection } from './components/Sidebar/ConnectionPanel';
 import QueryEditor, { QueryTab, QueryResult } from './components/MainArea/QueryEditor';
-import DataGrid from './components/MainArea/DataGrid';
+import DataGrid, { Column as GridColumn, DataRow as GridRow } from './components/MainArea/DataGrid';
 import TableStructure from './components/MainArea/TableStructure';
+import TableList from './components/MainArea/TableList';
+import NewConnectionDialog, { NewConnectionFormData } from './components/common/NewConnectionDialog';
 
-// Import mock data
+// Keep mock data for QueryEditor initial tabs
-import { mockConnections } from './mock/connections';
+import { mockQueryTabs } from './mock/queryResults';
-import { 
+import { TableColumn, Index, ForeignKey } from './components/MainArea/TableStructure';
-  mockQueryResults, 
-  mockQueryTabs, 
-  mockDataGridColumns, 
-  mockDataGridRows,
-  mockTableColumns,
-  mockIndexes,
-  mockForeignKeys,
-  mockTableInfo,
-} from './mock/queryResults';
 
-type MainView = 'query' | 'data' | 'structure';
+type MainView = 'query' | 'data' | 'structure' | 'tables';
+
+/** Map backend UserConnection to frontend DatabaseConnection */
+function toFrontendConn(c: models.UserConnection): DatabaseConnection {
+  return {
+    id: c.id,
+    name: c.name,
+    type: c.type === 'postgres' ? 'postgresql' : (c.type as any),
+    host: c.host,
+    port: c.port,
+    status: 'disconnected',
+  };
+}
 
 function App() {
-  // Application state
+  const [connections, setConnections] = useState<DatabaseConnection[]>([]);
-  const [connections] = useState<DatabaseConnection[]>(mockConnections);
+  const [activeConnectionId, setActiveConnectionId] = useState<string>('');
-  const [activeConnectionId, setActiveConnectionId] = useState<string>('conn-1');
+  const [selectedConnectionId, setSelectedConnectionId] = useState<string>('');
-  const [selectedConnectionId, setSelectedConnectionId] = useState<string>('conn-1');
   const [sidebarCollapsed, setSidebarCollapsed] = useState(false);
+  const [showNewConnDialog, setShowNewConnDialog] = useState(false);
+  const [editingConnection, setEditingConnection] = useState<DatabaseConnection | null>(null);
+  const [deleteConfirmId, setDeleteConfirmId] = useState<string | null>(null);
 
   // Query editor state
   const [queryTabs, setQueryTabs] = useState<QueryTab[]>(mockQueryTabs);
@@ -45,47 +66,339 @@ function App() {
   const [queryResults, setQueryResults] = useState<QueryResult | null>(null);
   const [isQueryLoading, setIsQueryLoading] = useState(false);
 
-  // Main view state
+  // DataGrid state
-  const [mainView, setMainView] = useState<MainView>('query');
+  const [selectedTable, setSelectedTable] = useState<{ name: string; schema: string } | null>(null);
+  const [dataGridColumns, setDataGridColumns] = useState<GridColumn[]>([]);
+  const [dataGridRows, setDataGridRows] = useState<GridRow[]>([]);
+  const [dataGridPage, setDataGridPage] = useState(1);
+  const [dataGridPageSize, setDataGridPageSize] = useState(50);
+  const [dataGridHasMore, setDataGridHasMore] = useState(false);
+  const [isDataGridLoading, setIsDataGridLoading] = useState(false);
+  const [dataGridError, setDataGridError] = useState<string | null>(null);
 
-  // Handler: Connection click
+  // TableStructure state
-  const handleConnectionClick = useCallback((connection: DatabaseConnection) => {
+  const [structureTable, setStructureTable] = useState<{ name: string; schema: string } | null>(null);
+  const [structureColumns, setStructureColumns] = useState<TableColumn[]>([]);
+  const [structureIndexes, setStructureIndexes] = useState<Index[]>([]);
+  const [structureForeignKeys, setStructureForeignKeys] = useState<ForeignKey[]>([]);
+  const [isStructureLoading, setIsStructureLoading] = useState(false);
+  const [structureError, setStructureError] = useState<string | null>(null);
+
+  // Main view state
+  const [mainView, setMainView] = useState<MainView>('tables');
+
+  // Load connections from backend on startup
+  const loadConnections = useCallback(async () => {
+    try {
+      const list = await GetConnections();
+      setConnections((list || []).map(toFrontendConn));
+    } catch (err) {
+      console.error('Failed to load connections:', err);
+    }
+  }, []);
+
+  useEffect(() => {
+    loadConnections();
+  }, [loadConnections]);
+
+  // Handler: click a connection — test + connect
+  const handleConnectionClick = useCallback(async (connection: DatabaseConnection) => {
     setSelectedConnectionId(connection.id);
-    if (connection.status === 'disconnected') {
+
-      console.log(`Connecting to ${connection.name}...`);
+    if (connection.status === 'disconnected' || connection.status === 'error') {
-      // In real app: call backend to connect
+      // Show connecting spinner
+      setConnections(prev =>
+        prev.map(c => c.id === connection.id
+          ? { ...c, status: 'connecting' as const, errorMessage: undefined }
+          : c)
+      );
+
+      try {
+        // Wails returns Promise<boolean|string>: boolean on success, string on failure
+        const testResult = await TestConnection(connection.id);
+        const success = testResult === true;
+        const message = typeof testResult === 'string' ? testResult : '';
+
+        if (success) {
+          setActiveConnectionId(connection.id);
+          // Load tables and group by schema
+          // Wails returns Promise<Table[]|string>: array on success, string on failure
+          const tablesResult = await GetTables(connection.id);
+          const tables: models.Table[] = Array.isArray(tablesResult) ? tablesResult : [];
+          const schemaMap: Record<string, Table[]> = {};
+          tables.forEach((t: models.Table) => {
+            const schemaName = t.schema || 'public';
+            if (!schemaMap[schemaName]) schemaMap[schemaName] = [];
+            schemaMap[schemaName].push({ id: t.name, name: t.name });
+          });
+          const databases: Schema[] = Object.entries(schemaMap).map(([name, tbls]) => ({
+            id: name,
+            name,
+            tables: tbls,
+          }));
+          setConnections(prev =>
+            prev.map(c => c.id === connection.id
+              ? { ...c, status: 'active' as const, databases }
+              : c)
+          );
+        } else {
+          setConnections(prev =>
+            prev.map(c => c.id === connection.id
+              ? { ...c, status: 'error' as const, errorMessage: message || 'Connection failed' }
+              : c)
+          );
+        }
+      } catch (err) {
+        setConnections(prev =>
+          prev.map(c => c.id === connection.id
+            ? { ...c, status: 'error' as const, errorMessage: String(err) }
+            : c)
+        );
+      }
     } else if (connection.status === 'connected' || connection.status === 'active') {
       setActiveConnectionId(connection.id);
     }
   }, []);
 
-  // Handler: New connection
+  // Handler: open new connection dialog
   const handleNewConnection = useCallback(() => {
-    console.log('Opening new connection dialog...');
+    setShowNewConnDialog(true);
-    // In real app: open connection dialog
   }, []);
 
-  // Handler: Table double-click
+  // Handler: create connection from dialog form
-  const handleTableDoubleClick = useCallback((
+  const handleCreateConnection = useCallback(async (data: NewConnectionFormData) => {
-    table: any,
+    const req = new models.CreateConnectionRequest();
-    schema: any,
+    req.name = data.name;
-    connection: DatabaseConnection
+    req.type = data.type;
+    req.host = data.host;
+    req.port = data.port;
+    req.username = data.username;
+    req.password = data.password;
+    req.database = data.database;
+    req.ssl_mode = data.ssl_mode;
+    req.timeout = data.timeout || 30;
+
+    const errMsg = await CreateConnection(req);
+    if (errMsg) {
+      throw new Error(errMsg);
+    }
+    setShowNewConnDialog(false);
+    await loadConnections();
+  }, [loadConnections]);
+
+  // Handler: edit connection — open dialog pre-filled
+  const handleEditConnection = useCallback((connection: DatabaseConnection) => {
+    setEditingConnection(connection);
+  }, []);
+
+  // Handler: save edited connection
+  const handleSaveEditedConnection = useCallback(async (data: NewConnectionFormData) => {
+    if (!editingConnection) return;
+    const conn = new models.UserConnection();
+    conn.id = editingConnection.id;
+    conn.name = data.name;
+    conn.type = data.type;
+    conn.host = data.host;
+    conn.port = data.port;
+    conn.username = data.username;
+    conn.password = data.password; // empty string = keep existing
+    conn.database = data.database;
+    conn.ssl_mode = data.ssl_mode;
+    conn.timeout = data.timeout || 30;
+    const errMsg = await UpdateConnection(conn);
+    if (errMsg) throw new Error(errMsg);
+    setEditingConnection(null);
+    await loadConnections();
+  }, [editingConnection, loadConnections]);
+
+  // Handler: delete connection (with inline confirm)
+  const handleDeleteConnection = useCallback(async (connection: DatabaseConnection) => {
+    if (deleteConfirmId !== connection.id) {
+      // First click: show confirm state
+      setDeleteConfirmId(connection.id);
+      // Auto-reset after 3s
+      setTimeout(() => setDeleteConfirmId(null), 3000);
+      return;
+    }
+    // Second click: actually delete
+    setDeleteConfirmId(null);
+    const errMsg = await DeleteConnection(connection.id);
+    if (errMsg) { console.error('Delete failed:', errMsg); return; }
+    if (activeConnectionId === connection.id) setActiveConnectionId('');
+    if (selectedConnectionId === connection.id) setSelectedConnectionId('');
+    setConnections(prev => prev.filter(c => c.id !== connection.id));
+  }, [deleteConfirmId, activeConnectionId, selectedConnectionId]);
+
+  // Handler: disconnect (close DB connection, keep config)
+  const handleDisconnectConnection = useCallback(async (connection: DatabaseConnection) => {
+    await DisconnectConnection(connection.id);
+    setConnections(prev =>
+      prev.map(c => c.id === connection.id ? { ...c, status: 'disconnected' as const, databases: undefined } : c)
+    );
+    if (activeConnectionId === connection.id) {
+      setActiveConnectionId('');
+      setSelectedTable(null);
+      setDataGridColumns([]);
+      setDataGridRows([]);
+    }
+  }, [activeConnectionId]);
+
+  // Load data for a table (page-based)
+  const loadTableData = useCallback(async (
+    connectionId: string,
+    tableName: string,
+    schema: string,
+    page: number,
+    pageSize: number,
   ) => {
-    console.log(`Opening table ${table.name} from schema ${schema.name}`);
+    setIsDataGridLoading(true);
+    setDataGridError(null);
+    const fullName = schema && schema !== 'public' ? `${schema}.${tableName}` : tableName;
+    const offset = (page - 1) * pageSize;
+    try {
+      const result = await GetTableData(connectionId, fullName, pageSize, offset);
+      if (typeof result === 'string') {
+        setDataGridError(result);
+        setDataGridColumns([]);
+        setDataGridRows([]);
+        setDataGridHasMore(false);
+      } else if (result) {
+        const r = result as models.QueryResult;
+        const cols: GridColumn[] = (r.columns || []).map(name => ({
+          id: name,
+          name,
+          sortable: false,
+          editable: false,
+        }));
+        const rows: GridRow[] = (r.rows || []).map((row, i) => {
+          const obj: GridRow = { id: offset + i };
+          (r.columns || []).forEach((col, j) => { obj[col] = row[j]; });
+          return obj;
+        });
+        setDataGridColumns(cols);
+        setDataGridRows(rows);
+        setDataGridHasMore(rows.length === pageSize);
+      }
+    } catch (err: any) {
+      setDataGridError(String(err));
+    } finally {
+      setIsDataGridLoading(false);
+    }
+  }, []);
+
+  // Open a table in the DataGrid view
+  const handleOpenTableData = useCallback(async (table: Table, schema: Schema) => {
+    setSelectedTable({ name: table.name, schema: schema.name });
+    setDataGridPage(1);
     setMainView('data');
+    await loadTableData(activeConnectionId, table.name, schema.name, 1, dataGridPageSize);
+  }, [activeConnectionId, dataGridPageSize, loadTableData]);
+
+  // Handler: Table double-click in sidebar
+  const handleTableDoubleClick = useCallback(async (
+    table: Table,
+    schema: Schema,
+    _connection: DatabaseConnection
+  ) => {
+    await handleOpenTableData(table, schema);
+  }, [handleOpenTableData]);
+
+  // Load structure for a table
+  const loadTableStructure = useCallback(async (connectionId: string, tableName: string, schema: string) => {
+    setIsStructureLoading(true);
+    setStructureError(null);
+    const fullName = schema && schema !== 'public' ? `${schema}.${tableName}` : tableName;
+    try {
+      const result = await GetTableStructure(connectionId, fullName);
+      if (typeof result === 'string') {
+        setStructureError(result);
+        setStructureColumns([]);
+        setStructureIndexes([]);
+        setStructureForeignKeys([]);
+      } else if (result) {
+        const s = result as models.TableStructure;
+        setStructureColumns((s.columns || []).map(c => ({
+          name: c.name,
+          type: c.data_type,
+          nullable: c.nullable,
+          isPrimaryKey: c.is_primary,
+          isUnique: c.is_unique,
+          defaultValue: c.default || undefined,
+          extra: c.auto_increment ? 'auto_increment' : undefined,
+        })));
+        setStructureIndexes((s.indexes || []).map(i => ({
+          name: i.name,
+          type: i.is_primary ? 'PRIMARY' : i.is_unique ? 'UNIQUE' : 'INDEX',
+          columns: i.columns || [],
+          isUnique: i.is_unique,
+          method: i.type || 'btree',
+        })));
+        setStructureForeignKeys((s.foreign_keys || []).map(fk => ({
+          name: fk.name,
+          column: (fk.columns || [])[0] || '',
+          referencesTable: fk.referenced_table,
+          referencesColumn: (fk.referenced_columns || [])[0] || '',
+          onUpdate: fk.on_update || undefined,
+          onDelete: fk.on_delete || undefined,
+        })));
+      }
+    } catch (err: any) {
+      setStructureError(String(err));
+    } finally {
+      setIsStructureLoading(false);
+    }
   }, []);
 
-  // Handler: Query execution
+  // Open a table in the Structure view
-  const handleExecuteQuery = useCallback((query: string) => {
+  const handleOpenTableStructure = useCallback(async (table: Table, schema: Schema) => {
+    setStructureTable({ name: table.name, schema: schema.name });
+    setMainView('structure');
+    await loadTableStructure(activeConnectionId, table.name, schema.name);
+  }, [activeConnectionId, loadTableStructure]);
+
+  // Handler: Query execution via Wails
+  const handleExecuteQuery = useCallback(async (query: string) => {
+    if (!query.trim()) return;
+    if (!activeConnectionId) {
+      setQueryResults({ columns: [], rows: [], rowCount: 0, executionTime: 0, error: 'No active connection. Connect to a database first.' });
+      return;
+    }
     setIsQueryLoading(true);
-    console.log('Executing query:', query);
+    setQueryResults(null);
-    
+    try {
-    // Simulate async query execution
+      // Wails returns Promise<QueryResult|string>: object on success, string on failure
-    setTimeout(() => {
+      const queryResult = await WailsExecuteQuery(activeConnectionId, query);
-      setQueryResults(mockQueryResults);
+      if (!queryResult) {
+        setQueryResults({ columns: [], rows: [], rowCount: 0, executionTime: 0, error: 'Query returned no result' });
+      } else if (typeof queryResult === 'string') {
+        setQueryResults({ columns: [], rows: [], rowCount: 0, executionTime: 0, error: queryResult });
+      } else {
+        const result = queryResult as models.QueryResult;
+        if (result.error) {
+          setQueryResults({ columns: [], rows: [], rowCount: 0, executionTime: 0, error: result.error });
+        } else {
+          const affectedRows = result.affected_rows || 0;
+          const hasData = Array.isArray(result.columns) && result.columns.length > 0;
+          const message = !hasData && affectedRows > 0
+            ? `${affectedRows} row(s) affected`
+            : !hasData
+              ? 'Query executed successfully'
+              : undefined;
+          setQueryResults({
+            columns: result.columns || [],
+            rows: result.rows || [],
+            rowCount: result.row_count || 0,
+            executionTime: result.duration_ms ? result.duration_ms / 1000 : 0,
+            message,
+          });
+        }
+      }
+    } catch (err: any) {
+      setQueryResults({ columns: [], rows: [], rowCount: 0, executionTime: 0, error: String(err) });
+    } finally {
       setIsQueryLoading(false);
-    }, 500);
+    }
-  }, []);
+  }, [activeConnectionId]);
 
   // Handler: Tab content change
   const handleContentChange = useCallback((tabId: string, content: string) => {
@@ -96,7 +409,6 @@ function App() {
 
   // Handler: Save query
   const handleSaveQuery = useCallback((tabId: string) => {
-    console.log('Saving query:', tabId);
     setQueryTabs(prev => prev.map(tab =>
       tab.id === tabId ? { ...tab, isDirty: false } : tab
     ));
@@ -122,47 +434,16 @@ function App() {
     setActiveTabId(newTab.id);
   }, []);
 
-  // Handler: Format SQL
+  // Handler: Format SQL (placeholder)
-  const handleFormatSQL = useCallback(() => {
+  const handleFormatSQL = useCallback(() => { }, []);
-    console.log('Formatting SQL...');
-    // In real app: format SQL using sql-formatter
-  }, []);
 
-  // Handler: Menu item click
-  const handleMenuItemClick = useCallback((menuId: string, itemId: string) => {
-    console.log(`Menu "${menuId}" -> Item "${itemId}"`);
-    
-    switch (itemId) {
-      case 'new-connection':
-        handleNewConnection();
-        break;
-      case 'run-query':
-        if (activeTabId) {
-          const tab = queryTabs.find(t => t.id === activeTabId);
-          if (tab) handleExecuteQuery(tab.content);
-        }
-        break;
-      case 'toggle-sidebar':
-        setSidebarCollapsed(prev => !prev);
-        break;
-      default:
-        console.log('Unhandled menu item:', itemId);
-    }
-  }, [activeTabId, queryTabs, handleNewConnection, handleExecuteQuery]);
-
-  // Get active connection
   const activeConnection = connections.find(c => c.id === activeConnectionId);
 
   return (
+    <>
       <AppLayout
         sidebarCollapsed={sidebarCollapsed}
         onSidebarToggle={setSidebarCollapsed}
-      menuBar={
-        <MenuBar 
-          title="uzdb"
-          onMenuItemClick={handleMenuItemClick}
-        />
-      }
         toolbar={
           <ToolBar
             buttons={[
@@ -200,6 +481,7 @@ function App() {
                 tooltip: 'Find in query (Ctrl+F)',
               },
             ]}
+            activeConnection={activeConnection ? { name: activeConnection.name, type: activeConnection.type } : null}
           />
         }
         sidebar={
@@ -210,12 +492,21 @@ function App() {
             onConnectionClick={handleConnectionClick}
             onNewConnection={handleNewConnection}
             onTableDoubleClick={handleTableDoubleClick}
+            onEdit={handleEditConnection}
+            onDelete={handleDeleteConnection}
+            onDisconnect={handleDisconnectConnection}
           />
         }
         mainContent={
           <div className="main-content">
             {/* View tabs */}
             <div className="view-tabs">
+              <button
+                className={`view-tab ${mainView === 'tables' ? 'active' : ''}`}
+                onClick={() => setMainView('tables')}
+              >
+                🗂 Tables
+              </button>
               <button
                 className={`view-tab ${mainView === 'query' ? 'active' : ''}`}
                 onClick={() => setMainView('query')}
@@ -244,6 +535,7 @@ function App() {
                   activeTabId={activeTabId}
                   results={queryResults}
                   isLoading={isQueryLoading}
+                  activeConnection={activeConnection ? { name: activeConnection.name, type: activeConnection.type } : undefined}
                   onTabClick={setActiveTabId}
                   onCloseTab={handleCloseTab}
                   onNewTab={handleNewTab}
@@ -254,53 +546,137 @@ function App() {
                 />
               )}
 
-            {mainView === 'data' && (
+              {mainView === 'data' && (() => {
+                // Compute total for pagination: if hasMore, signal there are more pages
+                const dgTotal = dataGridHasMore
+                  ? dataGridPage * dataGridPageSize + 1
+                  : (dataGridPage - 1) * dataGridPageSize + dataGridRows.length;
+
+                if (!selectedTable) {
+                  return (
+                    <div className="datagrid-empty-state">
+                      <div className="datagrid-empty-icon">📊</div>
+                      <p>No table selected</p>
+                      <span>Double-click a table in the sidebar or open one from the Tables view.</span>
+                    </div>
+                  );
+                }
+
+                return (
                   <DataGrid
-                columns={mockDataGridColumns}
+                    columns={dataGridColumns}
-                rows={mockDataGridRows}
+                    rows={dataGridRows}
-                totalRows={1247}
+                    totalRows={dgTotal}
-                pagination={{ currentPage: 1, pageSize: 25, totalRows: 1247 }}
+                    isLoading={isDataGridLoading}
+                    pagination={{ currentPage: dataGridPage, pageSize: dataGridPageSize, totalRows: dgTotal }}
                     selectable
-                editable
+                    editable={false}
-                tableName="users"
+                    tableName={selectedTable.name}
-                schemaName="public"
+                    schemaName={selectedTable.schema}
-                onRefresh={() => console.log('Refreshing data...')}
+                    onRefresh={() => loadTableData(activeConnectionId, selectedTable.name, selectedTable.schema, dataGridPage, dataGridPageSize)}
-                onExport={() => console.log('Exporting data...')}
+                    onExport={() => { }}
-                onAddRow={() => console.log('Adding row...')}
+                    onAddRow={() => { }}
+                    onPageChange={(page) => {
+                      setDataGridPage(page);
+                      loadTableData(activeConnectionId, selectedTable.name, selectedTable.schema, page, dataGridPageSize);
+                    }}
+                    onPageSizeChange={(size) => {
+                      setDataGridPageSize(size);
+                      setDataGridPage(1);
+                      loadTableData(activeConnectionId, selectedTable.name, selectedTable.schema, 1, size);
+                    }}
+                  />
+                );
+              })()}
+
+              {mainView === 'structure' && (() => {
+                if (!structureTable) {
+                  return (
+                    <div className="datagrid-empty-state">
+                      <div className="datagrid-empty-icon">📋</div>
+                      <p>No table selected</p>
+                      <span>Open a table from the Tables view or sidebar.</span>
+                    </div>
+                  );
+                }
+                if (isStructureLoading) {
+                  return (
+                    <div className="datagrid-empty-state">
+                      <div className="datagrid-empty-icon">⏳</div>
+                      <p>Loading structure…</p>
+                    </div>
+                  );
+                }
+                if (structureError) {
+                  return (
+                    <div className="datagrid-empty-state">
+                      <div className="datagrid-empty-icon">⚠️</div>
+                      <p>Failed to load structure</p>
+                      <span>{structureError}</span>
+                    </div>
+                  );
+                }
+                return (
+                  <TableStructure
+                    tableName={structureTable.name}
+                    schemaName={structureTable.schema}
+                    connectionName={activeConnection?.name}
+                    columns={structureColumns}
+                    indexes={structureIndexes}
+                    foreignKeys={structureForeignKeys}
+                    onViewData={() => {
+                      if (structureTable && activeConnection?.databases) {
+                        const schema = activeConnection.databases.find(s => s.name === structureTable.schema);
+                        const table = schema?.tables?.find(t => t.name === structureTable.name);
+                        if (schema && table) handleOpenTableData(table, schema);
+                        else setMainView('data');
+                      }
+                    }}
+                    onEditTable={() => { }}
+                    onRefresh={() => loadTableStructure(activeConnectionId, structureTable.name, structureTable.schema)}
+                  />
+                );
+              })()}
+
+              {mainView === 'tables' && (
+                <TableList
+                  schemas={activeConnection?.databases}
+                  connectionName={activeConnection?.name}
+                  onViewData={(table, schema) => handleOpenTableData(table, schema)}
+                  onViewStructure={(table, schema) => handleOpenTableStructure(table, schema)}
+                />
+              )}
+            </div>
+          </div>
+        }
+      />
+
+      {showNewConnDialog && (
+        <NewConnectionDialog
+          onConfirm={handleCreateConnection}
+          onCancel={() => setShowNewConnDialog(false)}
         />
       )}
 
-            {mainView === 'structure' && (
+      {editingConnection && (
-              <TableStructure
+        <NewConnectionDialog
-                tableName="users"
+          mode="edit"
-                schemaName="public"
+          initialData={{
-                connectionName={activeConnection?.name}
+            id: editingConnection.id,
-                columns={mockTableColumns}
+            name: editingConnection.name,
-                indexes={mockIndexes}
+            type: editingConnection.type === 'postgresql' ? 'postgres' : editingConnection.type as any,
-                foreignKeys={mockForeignKeys}
+            host: editingConnection.host ?? '',
-                tableInfo={mockTableInfo}
+            port: editingConnection.port ?? 0,
-                onViewData={() => setMainView('data')}
+            username: '',
-                onEditTable={() => console.log('Edit table...')}
+            database: '',
-                onRefresh={() => console.log('Refreshing structure...')}
+            ssl_mode: 'disable',
+            timeout: 30,
+          }}
+          onConfirm={handleSaveEditedConnection}
+          onCancel={() => setEditingConnection(null)}
         />
       )}
-          </div>
+    </>
-        </div>
-      }
-      statusBar={
-        <StatusBar
-          connectionInfo={activeConnection?.status === 'active' 
-            ? `✓ Connected to ${activeConnection.name}`
-            : 'Ready'
-          }
-          queryInfo={queryResults ? `${queryResults.rowCount} rows in ${queryResults.executionTime}s` : undefined}
-          statusType={queryResults?.error ? 'error' : queryResults ? 'success' : 'normal'}
-          encoding="UTF-8"
-          lineEnding="LF"
-          editorMode="ins"
-        />
-      }
-    />
   );
 }
 

frontend/src/components/Layout/ToolBar.css

@@ -92,6 +92,11 @@
   box-shadow: 0 0 4px var(--success);
 }
 
+.toolbar-connection.disconnected {
+  opacity: 0.5;
+  cursor: default;
+}
+
 .connection-name {
   font-size: var(--text-sm);
   font-weight: 500;

frontend/src/components/Layout/ToolBar.tsx

@@ -24,6 +24,8 @@ export interface ToolBarProps {
   children?: React.ReactNode;
   /** Handler when button is clicked */
   onButtonClick?: (buttonId: string) => void;
+  /** Active connection info for display */
+  activeConnection?: { name: string; type: string } | null;
 }
 
 /**
@@ -63,6 +65,7 @@ export const ToolBar: React.FC<ToolBarProps> = ({
   buttons = defaultButtons,
   children,
   onButtonClick,
+  activeConnection,
 }) => {
   const handleButtonClick = (button: ToolButton) => {
     button.onClick?.();
@@ -92,10 +95,13 @@ export const ToolBar: React.FC<ToolBarProps> = ({
       <div className="toolbar-spacer" />
 
       {/* Connection indicator */}
-      <div className="toolbar-connection">
+      <div className={`toolbar-connection ${activeConnection ? 'connected' : 'disconnected'}`}>
-        <span className="connection-status-dot connected"></span>
+        <span className={`connection-status-dot ${activeConnection ? 'connected' : ''}`}></span>
-        <span className="connection-name">🗄️ MySQL @ localhost</span>
+        <span className="connection-name">
-        <span className="dropdown-arrow">▼</span>
+          {activeConnection
+            ? `${activeConnection.type === 'postgresql' ? '🐘' : activeConnection.type === 'mysql' ? '🗄️' : '📁'} ${activeConnection.name}`
+            : 'No connection'}
+        </span>
       </div>
     </div>
   );

frontend/src/components/MainArea/QueryEditor.css

@@ -6,6 +6,7 @@
   display: flex;
   flex-direction: column;
   height: 100%;
+  position: relative;
   background-color: var(--bg-primary);
   overflow: hidden;
 }
@@ -133,17 +134,20 @@
   background-color: var(--bg-primary);
   border: 1px solid var(--border);
   border-radius: var(--radius-md);
-  cursor: pointer;
+  cursor: default;
   outline: none;
+  user-select: none;
+  white-space: nowrap;
 }
 
-.connection-select:hover {
+.connection-select.connected {
-  border-color: var(--text-secondary);
+  color: var(--success);
+  border-color: var(--success);
 }
 
-.connection-select:focus {
+.connection-select.disconnected {
-  border-color: var(--primary);
+  color: var(--text-muted);
-  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
+  font-style: italic;
 }
 
 /* Editor Container */
@@ -219,6 +223,15 @@
   border-bottom: 1px solid var(--border);
 }
 
+.results-header.error {
+  background-color: #fef2f2;
+  border-bottom-color: var(--error);
+}
+
+.results-header.error .results-title {
+  color: var(--error);
+}
+
 .results-title {
   font-size: var(--text-sm);
   font-weight: 600;
@@ -230,10 +243,23 @@
   color: var(--success);
 }
 
+.results-message.success {
+  color: var(--success);
+}
+
 .results-message.error {
   color: var(--error);
 }
 
+.results-error-summary {
+  flex: 1;
+  margin-left: var(--space-3);
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  cursor: default;
+}
+
 .results-table-wrapper {
   flex: 1;
   overflow: auto;

frontend/src/components/MainArea/QueryEditor.tsx

@@ -5,7 +5,7 @@
  * Based on layout-design.md section "SQL 编辑器模块"
  */
 
-import React, { useState, KeyboardEvent } from 'react';
+import React, { useState, useEffect, KeyboardEvent } from 'react';
 import './QueryEditor.css';
 
 export interface QueryTab {
@@ -47,6 +47,8 @@ export interface QueryEditorProps {
   onSave?: (tabId: string) => void;
   /** Handler when format is requested */
   onFormat?: () => void;
+  /** Active connection info for display */
+  activeConnection?: { name: string; type: string };
 }
 
 /**
@@ -64,6 +66,7 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
   onExecute,
   onSave,
   onFormat,
+  activeConnection,
 }) => {
   const [editorContent, setEditorContent] = useState('');
   const [cursorPosition, setCursorPosition] = useState({ line: 1, column: 1 });
@@ -71,6 +74,11 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
   // Get active tab
   const activeTab = tabs.find((t) => t.id === activeTabId);
 
+  // Sync local editorContent when active tab changes
+  useEffect(() => {
+    setEditorContent(activeTab?.content || '');
+  }, [activeTabId]);
+
   // Handle keyboard shortcuts
   const handleKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>) => {
     // Ctrl+Enter to execute
@@ -125,8 +133,7 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
           {tabs.map((tab) => (
             <div
               key={tab.id}
-              className={`query-tab ${tab.id === activeTabId ? 'active' : ''} ${
+              className={`query-tab ${tab.id === activeTabId ? 'active' : ''} ${tab.isDirty ? 'dirty' : ''
-                tab.isDirty ? 'dirty' : ''
                 }`}
               onClick={() => onTabClick?.(tab.id)}
             >
@@ -162,7 +169,7 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
           <button
             className="btn btn-primary btn-run"
             onClick={() => onExecute?.(editorContent)}
-            disabled={isLoading || !editorContent.trim()}
+            disabled={isLoading || !editorContent.trim() || !activeConnection}
           >
             ▶ Run
           </button>
@@ -191,10 +198,11 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
         </div>
         <div className="toolbar-spacer" />
         <div className="toolbar-group">
-          <select className="connection-select" disabled={isLoading}>
+          <span className={`connection-select ${activeConnection ? 'connected' : 'disconnected'}`}>
-            <option>🗄️ MySQL @ localhost</option>
+            {activeConnection
-            <option>🐘 PostgreSQL @ prod-db</option>
+              ? `${activeConnection.type === 'postgresql' ? '🐘' : activeConnection.type === 'mysql' ? '🗄️' : '📁'} ${activeConnection.name}`
-          </select>
+              : '⚠ No connection active'}
+          </span>
         </div>
       </div>
 
@@ -227,12 +235,19 @@ export const QueryEditor: React.FC<QueryEditorProps> = ({
 
       {/* Results Panel */}
       {results && (
-        <div className="results-panel">
+        <div className={`results-panel ${results.error ? 'has-error' : ''}`}>
-          <div className="results-header">
+          <div className={`results-header ${results.error ? 'error' : ''}`}>
-            <h4 className="results-title">Results</h4>
+            <h4 className="results-title">
-            {results.message && (
+              {results.error ? '✕ Error' : 'Results'}
-              <span className={`results-message ${results.error ? 'error' : 'success'}`}>
+            </h4>
-                {results.error ? '✕' : '✓'} {results.message}
+            {!results.error && results.message && (
+              <span className="results-message success">
+                ✓ {results.message}
+              </span>
+            )}
+            {results.error && (
+              <span className="results-message error results-error-summary" title={results.error}>
+                {results.error.length > 80 ? results.error.slice(0, 80) + '…' : results.error}
               </span>
             )}
           </div>

frontend/src/components/MainArea/TableList.css

@@ -0,0 +1,307 @@
+/**
+ * TableList Component Styles
+ */
+
+.table-list {
+    display: flex;
+    flex-direction: column;
+    height: 100%;
+    background-color: var(--bg-primary);
+    overflow: hidden;
+}
+
+/* ── Empty state ─────────────────────────────────── */
+.table-list-empty {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    height: 100%;
+    gap: var(--space-3);
+    color: var(--text-muted);
+}
+
+.table-list-empty-icon {
+    font-size: 40px;
+    line-height: 1;
+}
+
+.table-list-empty p {
+    margin: 0;
+    font-size: var(--text-base);
+    font-weight: 600;
+    color: var(--text-secondary);
+}
+
+.table-list-empty span {
+    font-size: var(--text-sm);
+}
+
+/* ── Header ──────────────────────────────────────── */
+.table-list-header {
+    display: flex;
+    flex-direction: column;
+    gap: var(--space-2);
+    padding: var(--space-3) var(--space-4);
+    background-color: var(--bg-tertiary);
+    border-bottom: 1px solid var(--border);
+    flex-shrink: 0;
+}
+
+.table-list-header-top {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+}
+
+.table-list-title {
+    display: flex;
+    align-items: baseline;
+    gap: var(--space-3);
+}
+
+.table-list-conn-name {
+    font-size: var(--text-sm);
+    font-weight: 600;
+    color: var(--text-primary);
+}
+
+.table-list-summary {
+    font-size: var(--text-xs);
+    color: var(--text-muted);
+}
+
+.table-list-search-row {
+    display: flex;
+    align-items: center;
+    gap: var(--space-2);
+    background-color: var(--bg-secondary);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-md);
+    padding: 0 var(--space-2);
+    transition: border-color var(--transition-fast) var(--ease-in-out);
+}
+
+.table-list-search-row:focus-within {
+    border-color: var(--primary);
+    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
+}
+
+.table-list-search-icon {
+    font-size: 13px;
+    color: var(--text-muted);
+    flex-shrink: 0;
+}
+
+.table-list-search {
+    flex: 1;
+    height: 30px;
+    background: transparent;
+    border: none;
+    outline: none;
+    font-size: var(--text-sm);
+    color: var(--text-primary);
+    font-family: var(--font-sans);
+}
+
+.table-list-search::placeholder {
+    color: var(--text-muted);
+}
+
+.table-list-search-clear {
+    width: 18px;
+    height: 18px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: transparent;
+    border: none;
+    border-radius: var(--radius-sm);
+    font-size: 14px;
+    color: var(--text-muted);
+    cursor: pointer;
+    flex-shrink: 0;
+    line-height: 1;
+}
+
+.table-list-search-clear:hover {
+    background-color: var(--bg-primary);
+    color: var(--text-primary);
+}
+
+/* ── Body ────────────────────────────────────────── */
+.table-list-body {
+    flex: 1;
+    overflow-y: auto;
+    padding: var(--space-2) 0;
+}
+
+.table-list-no-results {
+    padding: var(--space-6) var(--space-4);
+    text-align: center;
+    font-size: var(--text-sm);
+    color: var(--text-muted);
+}
+
+.table-list-search-info {
+    padding: var(--space-2) var(--space-4);
+    font-size: var(--text-xs);
+    color: var(--text-muted);
+    text-align: right;
+    border-top: 1px solid var(--border);
+    margin-top: var(--space-2);
+}
+
+/* ── Schema group ────────────────────────────────── */
+.table-list-schema {
+    margin-bottom: var(--space-1);
+}
+
+.table-list-schema-header {
+    display: flex;
+    align-items: center;
+    gap: var(--space-2);
+    padding: var(--space-2) var(--space-4);
+    cursor: pointer;
+    user-select: none;
+    background-color: var(--bg-secondary);
+    border-top: 1px solid var(--border);
+    border-bottom: 1px solid var(--border);
+}
+
+.table-list-schema-header:hover {
+    background-color: var(--bg-tertiary);
+}
+
+.table-list-schema-toggle {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 14px;
+    font-size: 10px;
+    color: var(--text-secondary);
+    transition: transform var(--transition-fast) var(--ease-in-out);
+    flex-shrink: 0;
+}
+
+.table-list-schema-toggle.expanded {
+    transform: rotate(90deg);
+}
+
+.table-list-schema-icon {
+    font-size: var(--text-sm);
+    flex-shrink: 0;
+}
+
+.table-list-schema-name {
+    font-size: var(--text-sm);
+    font-weight: 600;
+    color: var(--text-primary);
+    flex: 1;
+}
+
+.table-list-schema-count {
+    padding: 1px 7px;
+    font-size: 10px;
+    font-weight: 600;
+    color: var(--text-muted);
+    background-color: var(--bg-primary);
+    border: 1px solid var(--border);
+    border-radius: 9px;
+    line-height: 1.6;
+}
+
+/* ── Tables inside a schema ──────────────────────── */
+.table-list-tables {
+    display: flex;
+    flex-direction: column;
+}
+
+.table-list-col-headers {
+    display: flex;
+    align-items: center;
+    padding: var(--space-1) var(--space-4) var(--space-1) calc(var(--space-4) + 28px);
+    background-color: var(--bg-primary);
+    border-bottom: 1px solid var(--border);
+}
+
+.col-name {
+    flex: 1;
+    font-size: var(--text-xs);
+    font-weight: 600;
+    color: var(--text-muted);
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+}
+
+.col-actions {
+    font-size: var(--text-xs);
+    font-weight: 600;
+    color: var(--text-muted);
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    width: 140px;
+    text-align: right;
+}
+
+.table-list-row {
+    display: flex;
+    align-items: center;
+    padding: var(--space-2) var(--space-4);
+    gap: var(--space-2);
+    border-bottom: 1px solid var(--border);
+    transition: background-color var(--transition-fast) var(--ease-in-out);
+}
+
+.table-list-row:hover {
+    background-color: var(--bg-secondary);
+}
+
+.table-list-row:hover .table-list-row-actions {
+    opacity: 1;
+}
+
+.table-list-row-icon {
+    font-size: 13px;
+    flex-shrink: 0;
+}
+
+.table-list-row-name {
+    flex: 1;
+    font-size: var(--text-sm);
+    color: var(--text-primary);
+    font-family: var(--font-mono);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.table-list-row-actions {
+    display: flex;
+    gap: var(--space-1);
+    opacity: 0;
+    transition: opacity var(--transition-fast) var(--ease-in-out);
+    flex-shrink: 0;
+}
+
+.tl-action-btn {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    padding: 3px 8px;
+    font-size: var(--text-xs);
+    font-family: var(--font-sans);
+    color: var(--text-secondary);
+    background: transparent;
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    cursor: pointer;
+    white-space: nowrap;
+    transition: all var(--transition-fast) var(--ease-in-out);
+}
+
+.tl-action-btn:hover {
+    color: var(--primary);
+    border-color: var(--primary);
+    background-color: rgba(59, 130, 246, 0.06);
+}

frontend/src/components/MainArea/TableList.tsx

@@ -0,0 +1,176 @@
+/**
+ * TableList Component
+ *
+ * Shows all tables grouped by schema for the active connection,
+ * with search filtering and quick-action buttons.
+ */
+
+import React, { useState, useMemo } from 'react';
+import './TableList.css';
+import { Schema, Table } from '../Sidebar/ConnectionPanel';
+
+export interface TableListProps {
+    /** Schemas (with tables) from the active connection */
+    schemas?: Schema[];
+    /** Active connection name for display */
+    connectionName?: string;
+    /** Called when user wants to view table data */
+    onViewData?: (table: Table, schema: Schema) => void;
+    /** Called when user wants to view table structure */
+    onViewStructure?: (table: Table, schema: Schema) => void;
+}
+
+const TableList: React.FC<TableListProps> = ({
+    schemas = [],
+    connectionName,
+    onViewData,
+    onViewStructure,
+}) => {
+    const [search, setSearch] = useState('');
+    const [collapsedSchemas, setCollapsedSchemas] = useState<Set<string>>(new Set());
+
+    const toggleSchema = (id: string) => {
+        setCollapsedSchemas(prev => {
+            const next = new Set(prev);
+            next.has(id) ? next.delete(id) : next.add(id);
+            return next;
+        });
+    };
+
+    // Filter tables by search term
+    const filtered = useMemo(() => {
+        const q = search.trim().toLowerCase();
+        if (!q) return schemas;
+        return schemas
+            .map(schema => ({
+                ...schema,
+                tables: (schema.tables ?? []).filter(t =>
+                    t.name.toLowerCase().includes(q) || schema.name.toLowerCase().includes(q)
+                ),
+            }))
+            .filter(s => s.tables.length > 0);
+    }, [schemas, search]);
+
+    const totalTables = schemas.reduce((s, sc) => s + (sc.tables?.length ?? 0), 0);
+    const filteredTotal = filtered.reduce((s, sc) => s + (sc.tables?.length ?? 0), 0);
+
+    if (schemas.length === 0) {
+        return (
+            <div className="table-list">
+                <div className="table-list-empty">
+                    <div className="table-list-empty-icon">🔌</div>
+                    <p>No connection active</p>
+                    <span>Connect to a database to browse its tables.</span>
+                </div>
+            </div>
+        );
+    }
+
+    return (
+        <div className="table-list">
+            {/* Header bar */}
+            <div className="table-list-header">
+                <div className="table-list-header-top">
+                    <div className="table-list-title">
+                        <span className="table-list-conn-name">{connectionName ?? 'Tables'}</span>
+                        <span className="table-list-summary">
+                            {schemas.length} {schemas.length === 1 ? 'schema' : 'schemas'} · {totalTables} {totalTables === 1 ? 'table' : 'tables'}
+                        </span>
+                    </div>
+                </div>
+                <div className="table-list-search-row">
+                    <span className="table-list-search-icon">🔍</span>
+                    <input
+                        className="table-list-search"
+                        type="text"
+                        placeholder="Filter tables…"
+                        value={search}
+                        onChange={e => setSearch(e.target.value)}
+                        spellCheck={false}
+                    />
+                    {search && (
+                        <button
+                            className="table-list-search-clear"
+                            onClick={() => setSearch('')}
+                            title="Clear filter"
+                        >×</button>
+                    )}
+                </div>
+            </div>
+
+            {/* Table list body */}
+            <div className="table-list-body">
+                {filtered.length === 0 ? (
+                    <div className="table-list-no-results">
+                        No tables match <strong>"{search}"</strong>
+                    </div>
+                ) : (
+                    <>
+                        {filtered.map(schema => {
+                            const isCollapsed = collapsedSchemas.has(schema.id);
+                            const tables = schema.tables ?? [];
+
+                            return (
+                                <div key={schema.id} className="table-list-schema">
+                                    {/* Schema header */}
+                                    <div
+                                        className="table-list-schema-header"
+                                        onClick={() => toggleSchema(schema.id)}
+                                        role="button"
+                                        tabIndex={0}
+                                        onKeyDown={e => e.key === 'Enter' && toggleSchema(schema.id)}
+                                    >
+                                        <span className={`table-list-schema-toggle ${isCollapsed ? '' : 'expanded'}`}>▶</span>
+                                        <span className="table-list-schema-icon">📊</span>
+                                        <span className="table-list-schema-name">{schema.name}</span>
+                                        <span className="table-list-schema-count">{tables.length}</span>
+                                    </div>
+
+                                    {/* Tables */}
+                                    {!isCollapsed && (
+                                        <div className="table-list-tables">
+                                            {/* Column headings */}
+                                            <div className="table-list-col-headers">
+                                                <span className="col-name">Table name</span>
+                                                <span className="col-actions">Actions</span>
+                                            </div>
+                                            {tables.map(table => (
+                                                <div key={table.id} className="table-list-row">
+                                                    <span className="table-list-row-icon">📋</span>
+                                                    <span className="table-list-row-name">{table.name}</span>
+                                                    <div className="table-list-row-actions">
+                                                        <button
+                                                            className="tl-action-btn"
+                                                            title="View data"
+                                                            onClick={() => onViewData?.(table, schema)}
+                                                        >
+                                                            📊 Data
+                                                        </button>
+                                                        <button
+                                                            className="tl-action-btn"
+                                                            title="View structure"
+                                                            onClick={() => onViewStructure?.(table, schema)}
+                                                        >
+                                                            📋 Structure
+                                                        </button>
+                                                    </div>
+                                                </div>
+                                            ))}
+                                        </div>
+                                    )}
+                                </div>
+                            );
+                        })}
+                        {search && (
+                            <div className="table-list-search-info">
+                                Showing {filteredTotal} of {totalTables} tables
+                            </div>
+                        )}
+                    </>
+                )}
+            </div>
+        </div>
+    );
+};
+
+export default TableList;

frontend/src/components/Sidebar/ConnectionPanel.css

@@ -233,3 +233,76 @@
   background-color: var(--border);
   margin: var(--space-2) 0;
 }
+
+/* Connection action buttons (edit/disconnect/delete) */
+.connection-actions {
+  display: flex;
+  align-items: center;
+  gap: 2px;
+  margin-left: auto;
+  opacity: 0;
+  transition: opacity 0.15s;
+}
+
+.connection-item:hover .connection-actions {
+  opacity: 1;
+}
+
+.connection-action-btn {
+  padding: 3px 4px;
+  border-radius: var(--radius-sm);
+  background: transparent;
+  border: none;
+  cursor: pointer;
+  color: var(--text-secondary);
+  font-size: 13px;
+  line-height: 1;
+}
+
+.connection-action-btn:hover {
+  background: var(--bg-primary);
+  color: var(--text-primary);
+}
+
+.connection-action-btn.danger:hover {
+  color: #ef4444;
+}
+
+/* Connecting label */
+.connecting-label {
+  font-size: 11px;
+  color: var(--text-muted);
+  font-style: italic;
+  white-space: nowrap;
+}
+
+/* Connection error message */
+.connection-error-msg {
+  padding: 4px var(--space-4) 6px calc(var(--space-4) + 24px);
+  font-size: 11px;
+  color: #f87171;
+  line-height: 1.4;
+  word-break: break-word;
+}
+
+/* Connection stats (schema/table count summary) */
+.connection-stats {
+  padding: 2px var(--space-4) 6px calc(var(--space-4) + 24px);
+  font-size: 11px;
+  color: var(--text-muted);
+  line-height: 1.4;
+}
+
+/* Tree count badge */
+.tree-count-badge {
+  margin-left: auto;
+  padding: 1px 6px;
+  font-size: 10px;
+  font-weight: 600;
+  color: var(--text-muted);
+  background-color: var(--bg-primary);
+  border: 1px solid var(--border);
+  border-radius: 9px;
+  line-height: 1.6;
+  flex-shrink: 0;
+}

frontend/src/components/Sidebar/ConnectionPanel.tsx

@@ -5,7 +5,7 @@
  * Based on layout-design.md section "左侧连接面板设计"
  */
 
-import React, { useState, KeyboardEvent } from 'react';
+import React, { useState, useEffect, KeyboardEvent } from 'react';
 import { StatusIndicator, StatusType } from '../common/StatusIndicator';
 import './ConnectionPanel.css';
 
@@ -20,6 +20,7 @@ export interface DatabaseConnection {
   port?: number;
   status: StatusType;
   databases?: Schema[];
+  errorMessage?: string;
 }
 
 /**
@@ -84,6 +85,9 @@ export interface ConnectionPanelProps {
   onTableDoubleClick?: (table: Table, schema: Schema, connection: DatabaseConnection) => void;
   /** Collapsed state */
   collapsed?: boolean;
+  onEdit?: (connection: DatabaseConnection) => void;
+  onDelete?: (connection: DatabaseConnection) => void;
+  onDisconnect?: (connection: DatabaseConnection) => void;
 }
 
 /**
@@ -98,6 +102,7 @@ interface TreeNodeProps {
   children?: React.ReactNode;
   level: number;
   isActive?: boolean;
+  count?: number;
 }
 
 const TreeNode: React.FC<TreeNodeProps> = ({
@@ -109,6 +114,7 @@ const TreeNode: React.FC<TreeNodeProps> = ({
   children,
   level,
   isActive = false,
+  count,
 }) => {
   const hasChildren = children !== undefined && children !== null;
 
@@ -139,6 +145,9 @@ const TreeNode: React.FC<TreeNodeProps> = ({
         {!hasChildren && <span className="tree-toggle-placeholder" />}
         <span className="tree-icon">{icon}</span>
         <span className="tree-label">{label}</span>
+        {count !== undefined && (
+          <span className="tree-count-badge">{count}</span>
+        )}
       </div>
       {expanded && children && (
         <div className="tree-node-children" role="group">
@@ -163,6 +172,9 @@ interface ConnectionItemProps {
   onClick: () => void;
   onContextMenu: (event: React.MouseEvent) => void;
   onTableDoubleClick: (table: Table, schema: Schema) => void;
+  onEdit: () => void;
+  onDelete: () => void;
+  onDisconnect: () => void;
 }
 
 const ConnectionItem: React.FC<ConnectionItemProps> = ({
@@ -176,6 +188,9 @@ const ConnectionItem: React.FC<ConnectionItemProps> = ({
   onClick,
   onContextMenu,
   onTableDoubleClick,
+  onEdit,
+  onDelete,
+  onDisconnect,
 }) => {
   // Get database type icon
   const getDbTypeIcon = (): string => {
@@ -206,13 +221,53 @@ const ConnectionItem: React.FC<ConnectionItemProps> = ({
         <StatusIndicator status={connection.status} />
         <span className="db-type-icon">{getDbTypeIcon()}</span>
         <span className="connection-name">{connection.name}</span>
+        {connection.status === 'connecting' && (
+          <span className="connecting-label">connecting…</span>
+        )}
+        <div className="connection-actions">
+          <button
+            className="connection-action-btn"
+            title="Edit"
+            onClick={(e) => { e.stopPropagation(); onEdit(); }}
+          >✏️</button>
+          {(connection.status === 'connected' || connection.status === 'active') && (
+            <button
+              className="connection-action-btn"
+              title="Disconnect"
+              onClick={(e) => { e.stopPropagation(); onDisconnect(); }}
+            >⏹</button>
+          )}
+          <button
+            className="connection-action-btn danger"
+            title="Delete"
+            onClick={(e) => { e.stopPropagation(); onDelete(); }}
+          >🗑</button>
         </div>
+      </div>
+
+      {connection.status === 'error' && connection.errorMessage && (
+        <div className="connection-error-msg">{connection.errorMessage}</div>
+      )}
+
+      {/* Summary stats when connected */}
+      {(connection.status === 'connected' || connection.status === 'active') &&
+        connection.databases && (() => {
+          const totalTables = connection.databases.reduce((sum, s) => sum + (s.tables?.length ?? 0), 0);
+          const schemaCount = connection.databases.length;
+          return (
+            <div className="connection-stats">
+              {schemaCount} {schemaCount === 1 ? 'schema' : 'schemas'} · {totalTables} {totalTables === 1 ? 'table' : 'tables'}
+            </div>
+          );
+        })()
+      }
 
       {/* Schema tree - only show if connected and has databases */}
       {(connection.status === 'connected' || connection.status === 'active') &&
         connection.databases &&
         connection.databases.map((schema) => {
           const isSchemaExpanded = expandedSchemas.has(schema.id);
+          const tableCount = schema.tables?.length ?? 0;
 
           return (
             <TreeNode
@@ -222,6 +277,7 @@ const ConnectionItem: React.FC<ConnectionItemProps> = ({
               level={1}
               expanded={isSchemaExpanded}
               onToggle={() => onToggleSchema(schema.id)}
+              count={tableCount}
             >
               {/* Tables */}
               {schema.tables && schema.tables.length > 0 && (
@@ -289,11 +345,29 @@ export const ConnectionPanel: React.FC<ConnectionPanelProps> = ({
   onContextMenu,
   onTableDoubleClick,
   collapsed = false,
+  onEdit,
+  onDelete,
+  onDisconnect,
 }) => {
   // Track expanded schemas and tables
   const [expandedSchemas, setExpandedSchemas] = useState<Set<string>>(new Set());
   const [expandedTables, setExpandedTables] = useState<Set<string>>(new Set());
 
+  // Auto-expand first schema when connection databases are newly populated
+  useEffect(() => {
+    connections.forEach(conn => {
+      if (conn.databases && conn.databases.length > 0) {
+        const firstSchemaId = conn.databases[0].id;
+        setExpandedSchemas(prev => {
+          if (prev.has(firstSchemaId)) return prev;
+          const next = new Set(prev);
+          next.add(firstSchemaId);
+          return next;
+        });
+      }
+    });
+  }, [connections]);
+
   // Toggle schema expansion
   const handleToggleSchema = (schemaId: string) => {
     setExpandedSchemas((prev) => {
@@ -416,6 +490,9 @@ export const ConnectionPanel: React.FC<ConnectionPanelProps> = ({
               onTableDoubleClick={(table, schema) =>
                 onTableDoubleClick?.(table, schema, connection)
               }
+              onEdit={() => onEdit?.(connection)}
+              onDelete={() => onDelete?.(connection)}
+              onDisconnect={() => onDisconnect?.(connection)}
             />
           ))
         )}

frontend/src/components/common/NewConnectionDialog.css

@@ -0,0 +1,154 @@
+/* NewConnectionDialog Styles */
+
+.dialog-overlay {
+    position: fixed;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.55);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    z-index: 1000;
+    backdrop-filter: blur(2px);
+}
+
+.dialog-box {
+    background: var(--bg-secondary);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-lg);
+    width: 480px;
+    max-width: 95vw;
+    max-height: 90vh;
+    overflow-y: auto;
+    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.4);
+}
+
+.dialog-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: var(--space-5) var(--space-6);
+    border-bottom: 1px solid var(--border);
+}
+
+.dialog-title {
+    font-size: var(--text-lg);
+    font-weight: 600;
+    color: var(--text-primary);
+    margin: 0;
+}
+
+.dialog-close {
+    font-size: var(--text-base);
+    color: var(--text-secondary);
+}
+
+.dialog-form {
+    padding: var(--space-5) var(--space-6);
+    display: flex;
+    flex-direction: column;
+    gap: var(--space-4);
+}
+
+/* Type selector */
+.type-selector {
+    display: flex;
+    gap: var(--space-2);
+}
+
+.type-btn {
+    flex: 1;
+    padding: var(--space-3) var(--space-2);
+    font-size: var(--text-sm);
+    font-family: var(--font-sans);
+    font-weight: 500;
+    color: var(--text-secondary);
+    background: var(--bg-tertiary);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-md);
+    cursor: pointer;
+    transition: all var(--transition-fast) var(--ease-in-out);
+    white-space: nowrap;
+}
+
+.type-btn:hover {
+    color: var(--text-primary);
+    border-color: var(--text-secondary);
+}
+
+.type-btn.active {
+    color: var(--primary);
+    border-color: var(--primary);
+    background: rgba(59, 130, 246, 0.1);
+}
+
+/* Form groups */
+.form-group {
+    display: flex;
+    flex-direction: column;
+    gap: var(--space-2);
+}
+
+.form-group.flex-1 {
+    flex: 1;
+}
+
+.form-group.flex-3 {
+    flex: 3;
+}
+
+.form-row {
+    display: flex;
+    gap: var(--space-3);
+}
+
+.form-label {
+    font-size: var(--text-sm);
+    font-weight: 500;
+    color: var(--text-secondary);
+}
+
+.required {
+    color: #ef4444;
+}
+
+.form-input {
+    padding: var(--space-2) var(--space-3);
+    font-size: var(--text-sm);
+    font-family: var(--font-sans);
+    color: var(--text-primary);
+    background: var(--bg-primary);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-md);
+    outline: none;
+    transition: border-color var(--transition-fast) var(--ease-in-out);
+    width: 100%;
+    box-sizing: border-box;
+}
+
+.form-input:focus {
+    border-color: var(--primary);
+}
+
+.form-input::placeholder {
+    color: var(--text-muted);
+}
+
+/* Error */
+.form-error {
+    padding: var(--space-3);
+    background: rgba(239, 68, 68, 0.1);
+    border: 1px solid rgba(239, 68, 68, 0.4);
+    border-radius: var(--radius-md);
+    font-size: var(--text-sm);
+    color: #f87171;
+}
+
+/* Actions */
+.dialog-actions {
+    display: flex;
+    justify-content: flex-end;
+    gap: var(--space-3);
+    padding-top: var(--space-2);
+    border-top: 1px solid var(--border);
+    margin-top: var(--space-2);
+}

frontend/src/components/common/NewConnectionDialog.tsx

@@ -0,0 +1,210 @@
+/**
+ * NewConnectionDialog Component
+ * Modal form for creating a new database connection.
+ */
+
+import React, { useState } from 'react';
+import './NewConnectionDialog.css';
+
+export interface NewConnectionFormData {
+    name: string;
+    type: 'mysql' | 'postgres' | 'sqlite';
+    host: string;
+    port: number;
+    username: string;
+    password: string;
+    database: string;
+    ssl_mode: string;
+    timeout: number;
+}
+
+interface NewConnectionDialogProps {
+    onConfirm: (data: NewConnectionFormData) => Promise<void>;
+    onCancel: () => void;
+    initialData?: Partial<NewConnectionFormData> & { id?: string };
+    mode?: 'create' | 'edit';
+}
+
+const DEFAULT_PORTS: Record<string, number> = {
+    mysql: 3306,
+    postgres: 5432,
+    sqlite: 0,
+};
+
+const NewConnectionDialog: React.FC<NewConnectionDialogProps> = ({ onConfirm, onCancel, initialData, mode = 'create' }) => {
+    const isEditMode = mode === 'edit';
+    const [form, setForm] = useState<NewConnectionFormData>({
+        name: initialData?.name ?? '',
+        type: initialData?.type ?? 'postgres',
+        host: initialData?.host ?? '',
+        port: initialData?.port ?? 5432,
+        username: initialData?.username ?? '',
+        password: '',
+        database: initialData?.database ?? '',
+        ssl_mode: initialData?.ssl_mode ?? 'disable',
+        timeout: initialData?.timeout ?? 30,
+    });
+    const [loading, setLoading] = useState(false);
+    const [error, setError] = useState('');
+
+    const handleTypeChange = (type: NewConnectionFormData['type']) => {
+        setForm((prev) => ({
+            ...prev,
+            type,
+            port: DEFAULT_PORTS[type] || 0,
+        }));
+    };
+
+    const handleChange = (field: keyof NewConnectionFormData, value: string | number) => {
+        setForm((prev) => ({ ...prev, [field]: value }));
+    };
+
+    const handleSubmit = async (e: React.FormEvent) => {
+        e.preventDefault();
+        setError('');
+        setLoading(true);
+        try {
+            await onConfirm(form);
+        } catch (err: any) {
+            setError(err?.message || String(err));
+        } finally {
+            setLoading(false);
+        }
+    };
+
+    const isSQLite = form.type === 'sqlite';
+
+    return (
+        <div className="dialog-overlay" onClick={onCancel}>
+            <div className="dialog-box" onClick={(e) => e.stopPropagation()}>
+                <div className="dialog-header">
+                    <h2 className="dialog-title">{isEditMode ? 'Edit Connection' : 'New Connection'}</h2>
+                    <button className="btn-icon dialog-close" onClick={onCancel} aria-label="Close">✕</button>
+                </div>
+
+                <form className="dialog-form" onSubmit={handleSubmit}>
+                    {/* Connection Type */}
+                    <div className="form-group">
+                        <label className="form-label">Database Type</label>
+                        <div className="type-selector">
+                            {(['postgres', 'mysql', 'sqlite'] as const).map((t) => (
+                                <button
+                                    key={t}
+                                    type="button"
+                                    className={`type-btn ${form.type === t ? 'active' : ''}`}
+                                    onClick={() => handleTypeChange(t)}
+                                    disabled={isEditMode}
+                                >
+                                    {t === 'postgres' ? '🐘 PostgreSQL' : t === 'mysql' ? '🗄️ MySQL' : '◪ SQLite'}
+                                </button>
+                            ))}
+                        </div>
+                    </div>
+
+                    {/* Name */}
+                    <div className="form-group">
+                        <label className="form-label" htmlFor="conn-name">Connection Name <span className="required">*</span></label>
+                        <input
+                            id="conn-name"
+                            className="form-input"
+                            type="text"
+                            placeholder="e.g. My Postgres DB"
+                            value={form.name}
+                            onChange={(e) => handleChange('name', e.target.value)}
+                            required
+                            autoFocus
+                        />
+                    </div>
+
+                    {!isSQLite && (
+                        <>
+                            {/* Host & Port */}
+                            <div className="form-row">
+                                <div className="form-group flex-3">
+                                    <label className="form-label" htmlFor="conn-host">Host <span className="required">*</span></label>
+                                    <input
+                                        id="conn-host"
+                                        className="form-input"
+                                        type="text"
+                                        placeholder="127.0.0.1"
+                                        value={form.host}
+                                        onChange={(e) => handleChange('host', e.target.value)}
+                                        required
+                                    />
+                                </div>
+                                <div className="form-group flex-1">
+                                    <label className="form-label" htmlFor="conn-port">Port <span className="required">*</span></label>
+                                    <input
+                                        id="conn-port"
+                                        className="form-input"
+                                        type="number"
+                                        min={1}
+                                        max={65535}
+                                        value={form.port}
+                                        onChange={(e) => handleChange('port', parseInt(e.target.value, 10) || 0)}
+                                        required
+                                    />
+                                </div>
+                            </div>
+
+                            {/* Username & Password */}
+                            <div className="form-row">
+                                <div className="form-group flex-1">
+                                    <label className="form-label" htmlFor="conn-user">Username</label>
+                                    <input
+                                        id="conn-user"
+                                        className="form-input"
+                                        type="text"
+                                        placeholder="postgres"
+                                        value={form.username}
+                                        onChange={(e) => handleChange('username', e.target.value)}
+                                    />
+                                </div>
+                                <div className="form-group flex-1">
+                                    <label className="form-label" htmlFor="conn-pass">Password</label>
+                                    <input
+                                        id="conn-pass"
+                                        className="form-input"
+                                        type="password"
+                                        placeholder={isEditMode ? 'Leave blank to keep current' : '••••••••'}
+                                        value={form.password}
+                                        onChange={(e) => handleChange('password', e.target.value)}
+                                    />
+                                </div>
+                            </div>
+                        </>
+                    )}
+
+                    {/* Database / File */}
+                    <div className="form-group">
+                        <label className="form-label" htmlFor="conn-db">
+                            {isSQLite ? 'File Path' : 'Database'} <span className="required">*</span>
+                        </label>
+                        <input
+                            id="conn-db"
+                            className="form-input"
+                            type="text"
+                            placeholder={isSQLite ? '/path/to/db.sqlite' : 'postgres'}
+                            value={form.database}
+                            onChange={(e) => handleChange('database', e.target.value)}
+                            required
+                        />
+                    </div>
+
+                    {error && <div className="form-error">{error}</div>}
+
+                    <div className="dialog-actions">
+                        <button type="button" className="btn btn-secondary" onClick={onCancel} disabled={loading}>
+                            Cancel
+                        </button>
+                        <button type="submit" className="btn btn-primary" disabled={loading}>
+                            {loading ? (isEditMode ? 'Saving…' : 'Connecting…') : (isEditMode ? 'Save Changes' : 'Create Connection')}
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    );
+};
+
+export default NewConnectionDialog;

frontend/src/components/index.ts

@@ -8,6 +8,9 @@
 export { StatusIndicator } from './common/StatusIndicator';
 export type { StatusIndicatorProps, StatusType } from './common/StatusIndicator';
 
+export { default as NewConnectionDialog } from './common/NewConnectionDialog';
+export type { NewConnectionFormData } from './common/NewConnectionDialog';
+
 // Layout components
 export { AppLayout } from './Layout/AppLayout';
 export type { AppLayoutProps } from './Layout/AppLayout';

frontend/tsconfig.json

@@ -21,7 +21,8 @@
     "jsx": "react-jsx"
   },
   "include": [
-    "src"
+    "src",
+    "wailsjs"
   ],
   "references": [
     {

frontend/wailsjs/go/app/App.d.ts

@@ -0,0 +1,45 @@
+// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
+// This file is automatically generated. DO NOT EDIT
+import {models} from '../models';
+import {config} from '../models';
+import {services} from '../models';
+import {handler} from '../models';
+import {context} from '../models';
+
+export function CreateConnection(arg1:models.CreateConnectionRequest):Promise<string>;
+
+export function CreateSavedQuery(arg1:models.CreateSavedQueryRequest):Promise<models.SavedQuery|string>;
+
+export function DeleteConnection(arg1:string):Promise<string>;
+
+export function DeleteSavedQuery(arg1:number):Promise<string>;
+
+export function DisconnectConnection(arg1:string):Promise<string>;
+
+export function ExecuteQuery(arg1:string,arg2:string):Promise<models.QueryResult|string>;
+
+export function GetConnections():Promise<Array<models.UserConnection>>;
+
+export function GetQueryHistory(arg1:string,arg2:number,arg3:number):Promise<Array<models.QueryHistory>>;
+
+export function GetSavedQueries(arg1:string):Promise<Array<models.SavedQuery>|string>;
+
+export function GetTableData(arg1:string,arg2:string,arg3:number,arg4:number):Promise<models.QueryResult|string>;
+
+export function GetTableStructure(arg1:string,arg2:string):Promise<models.TableStructure|string>;
+
+export function GetTables(arg1:string):Promise<Array<models.Table>|string>;
+
+export function Initialize(arg1:config.Config,arg2:services.ConnectionService,arg3:services.QueryService,arg4:handler.HTTPServer):Promise<void>;
+
+export function OnStartup(arg1:context.Context):Promise<void>;
+
+export function Shutdown():Promise<void>;
+
+export function StartHTTPServer():Promise<string>;
+
+export function TestConnection(arg1:string):Promise<boolean|string>;
+
+export function UpdateConnection(arg1:models.UserConnection):Promise<string>;
+
+export function UpdateSavedQuery(arg1:number,arg2:models.UpdateSavedQueryRequest):Promise<models.SavedQuery|string>;

frontend/wailsjs/go/app/App.js

@@ -0,0 +1,79 @@
+// @ts-check
+// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
+// This file is automatically generated. DO NOT EDIT
+
+export function CreateConnection(arg1) {
+  return window['go']['app']['App']['CreateConnection'](arg1);
+}
+
+export function CreateSavedQuery(arg1) {
+  return window['go']['app']['App']['CreateSavedQuery'](arg1);
+}
+
+export function DeleteConnection(arg1) {
+  return window['go']['app']['App']['DeleteConnection'](arg1);
+}
+
+export function DeleteSavedQuery(arg1) {
+  return window['go']['app']['App']['DeleteSavedQuery'](arg1);
+}
+
+export function DisconnectConnection(arg1) {
+  return window['go']['app']['App']['DisconnectConnection'](arg1);
+}
+
+export function ExecuteQuery(arg1, arg2) {
+  return window['go']['app']['App']['ExecuteQuery'](arg1, arg2);
+}
+
+export function GetConnections() {
+  return window['go']['app']['App']['GetConnections']();
+}
+
+export function GetQueryHistory(arg1, arg2, arg3) {
+  return window['go']['app']['App']['GetQueryHistory'](arg1, arg2, arg3);
+}
+
+export function GetSavedQueries(arg1) {
+  return window['go']['app']['App']['GetSavedQueries'](arg1);
+}
+
+export function GetTableData(arg1, arg2, arg3, arg4) {
+  return window['go']['app']['App']['GetTableData'](arg1, arg2, arg3, arg4);
+}
+
+export function GetTableStructure(arg1, arg2) {
+  return window['go']['app']['App']['GetTableStructure'](arg1, arg2);
+}
+
+export function GetTables(arg1) {
+  return window['go']['app']['App']['GetTables'](arg1);
+}
+
+export function Initialize(arg1, arg2, arg3, arg4) {
+  return window['go']['app']['App']['Initialize'](arg1, arg2, arg3, arg4);
+}
+
+export function OnStartup(arg1) {
+  return window['go']['app']['App']['OnStartup'](arg1);
+}
+
+export function Shutdown() {
+  return window['go']['app']['App']['Shutdown']();
+}
+
+export function StartHTTPServer() {
+  return window['go']['app']['App']['StartHTTPServer']();
+}
+
+export function TestConnection(arg1) {
+  return window['go']['app']['App']['TestConnection'](arg1);
+}
+
+export function UpdateConnection(arg1) {
+  return window['go']['app']['App']['UpdateConnection'](arg1);
+}
+
+export function UpdateSavedQuery(arg1, arg2) {
+  return window['go']['app']['App']['UpdateSavedQuery'](arg1, arg2);
+}

frontend/wailsjs/go/main/App.d.ts

@@ -1,4 +0,0 @@
-// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
-// This file is automatically generated. DO NOT EDIT
-
-export function Greet(arg1:string):Promise<string>;

frontend/wailsjs/go/main/App.js

@@ -1,7 +0,0 @@
-// @ts-check
-// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
-// This file is automatically generated. DO NOT EDIT
-
-export function Greet(arg1) {
-  return window['go']['main']['App']['Greet'](arg1);
-}

frontend/wailsjs/go/models.ts

@@ -0,0 +1,529 @@
+export namespace config {
+	
+	export class APIConfig {
+	    enabled: boolean;
+	    port: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new APIConfig(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.enabled = source["enabled"];
+	        this.port = source["port"];
+	    }
+	}
+	export class LoggerConfig {
+	    level: string;
+	    format: string;
+	    output_path: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new LoggerConfig(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.level = source["level"];
+	        this.format = source["format"];
+	        this.output_path = source["output_path"];
+	    }
+	}
+	export class EncryptionConfig {
+	    key_file: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new EncryptionConfig(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.key_file = source["key_file"];
+	    }
+	}
+	export class DatabaseConfig {
+	    sqlite_path: string;
+	    max_open_conns: number;
+	    max_idle_conns: number;
+	    max_lifetime: number;
+	
+	    static createFrom(source: any = {}) {
+	        return new DatabaseConfig(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.sqlite_path = source["sqlite_path"];
+	        this.max_open_conns = source["max_open_conns"];
+	        this.max_idle_conns = source["max_idle_conns"];
+	        this.max_lifetime = source["max_lifetime"];
+	    }
+	}
+	export class Config {
+	    app_name: string;
+	    version: string;
+	    environment: string;
+	    database: DatabaseConfig;
+	    encryption: EncryptionConfig;
+	    logger: LoggerConfig;
+	    api: APIConfig;
+	
+	    static createFrom(source: any = {}) {
+	        return new Config(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.app_name = source["app_name"];
+	        this.version = source["version"];
+	        this.environment = source["environment"];
+	        this.database = this.convertValues(source["database"], DatabaseConfig);
+	        this.encryption = this.convertValues(source["encryption"], EncryptionConfig);
+	        this.logger = this.convertValues(source["logger"], LoggerConfig);
+	        this.api = this.convertValues(source["api"], APIConfig);
+	    }
+	
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
+	
+	
+
+}
+
+export namespace handler {
+	
+	export class HTTPServer {
+	
+	
+	    static createFrom(source: any = {}) {
+	        return new HTTPServer(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	
+	    }
+	}
+
+}
+
+export namespace models {
+	
+	export class CreateConnectionRequest {
+	    name: string;
+	    type: string;
+	    host: string;
+	    port: number;
+	    username: string;
+	    password: string;
+	    database: string;
+	    ssl_mode: string;
+	    timeout: number;
+	
+	    static createFrom(source: any = {}) {
+	        return new CreateConnectionRequest(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.type = source["type"];
+	        this.host = source["host"];
+	        this.port = source["port"];
+	        this.username = source["username"];
+	        this.password = source["password"];
+	        this.database = source["database"];
+	        this.ssl_mode = source["ssl_mode"];
+	        this.timeout = source["timeout"];
+	    }
+	}
+	export class CreateSavedQueryRequest {
+	    name: string;
+	    description: string;
+	    sql: string;
+	    connection_id: string;
+	    tags: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new CreateSavedQueryRequest(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.description = source["description"];
+	        this.sql = source["sql"];
+	        this.connection_id = source["connection_id"];
+	        this.tags = source["tags"];
+	    }
+	}
+	export class ForeignKey {
+	    name: string;
+	    columns: string[];
+	    referenced_table: string;
+	    referenced_columns: string[];
+	    on_delete?: string;
+	    on_update?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new ForeignKey(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.columns = source["columns"];
+	        this.referenced_table = source["referenced_table"];
+	        this.referenced_columns = source["referenced_columns"];
+	        this.on_delete = source["on_delete"];
+	        this.on_update = source["on_update"];
+	    }
+	}
+	export class QueryHistory {
+	    id: number;
+	    connection_id: string;
+	    sql: string;
+	    duration_ms: number;
+	    // Go type: time
+	    executed_at: any;
+	    rows_affected: number;
+	    error?: string;
+	    success: boolean;
+	    result_preview?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new QueryHistory(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.id = source["id"];
+	        this.connection_id = source["connection_id"];
+	        this.sql = source["sql"];
+	        this.duration_ms = source["duration_ms"];
+	        this.executed_at = this.convertValues(source["executed_at"], null);
+	        this.rows_affected = source["rows_affected"];
+	        this.error = source["error"];
+	        this.success = source["success"];
+	        this.result_preview = source["result_preview"];
+	    }
+	
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
+	export class QueryResult {
+	    columns: string[];
+	    rows: any[][];
+	    row_count: number;
+	    affected_rows: number;
+	    duration_ms: number;
+	    success: boolean;
+	    error?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new QueryResult(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.columns = source["columns"];
+	        this.rows = source["rows"];
+	        this.row_count = source["row_count"];
+	        this.affected_rows = source["affected_rows"];
+	        this.duration_ms = source["duration_ms"];
+	        this.success = source["success"];
+	        this.error = source["error"];
+	    }
+	}
+	export class SavedQuery {
+	    id: number;
+	    name: string;
+	    description: string;
+	    sql: string;
+	    connection_id: string;
+	    tags: string;
+	    // Go type: time
+	    created_at: any;
+	    // Go type: time
+	    updated_at: any;
+	
+	    static createFrom(source: any = {}) {
+	        return new SavedQuery(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.id = source["id"];
+	        this.name = source["name"];
+	        this.description = source["description"];
+	        this.sql = source["sql"];
+	        this.connection_id = source["connection_id"];
+	        this.tags = source["tags"];
+	        this.created_at = this.convertValues(source["created_at"], null);
+	        this.updated_at = this.convertValues(source["updated_at"], null);
+	    }
+	
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
+	export class Table {
+	    name: string;
+	    schema?: string;
+	    type: string;
+	    row_count?: number;
+	    description?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new Table(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.schema = source["schema"];
+	        this.type = source["type"];
+	        this.row_count = source["row_count"];
+	        this.description = source["description"];
+	    }
+	}
+	export class TableColumn {
+	    name: string;
+	    data_type: string;
+	    nullable: boolean;
+	    default?: string;
+	    is_primary: boolean;
+	    is_unique: boolean;
+	    auto_increment: boolean;
+	    length?: number;
+	    scale?: number;
+	    comment?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new TableColumn(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.data_type = source["data_type"];
+	        this.nullable = source["nullable"];
+	        this.default = source["default"];
+	        this.is_primary = source["is_primary"];
+	        this.is_unique = source["is_unique"];
+	        this.auto_increment = source["auto_increment"];
+	        this.length = source["length"];
+	        this.scale = source["scale"];
+	        this.comment = source["comment"];
+	    }
+	}
+	export class TableIndex {
+	    name: string;
+	    columns: string[];
+	    is_unique: boolean;
+	    is_primary: boolean;
+	    type?: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new TableIndex(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.columns = source["columns"];
+	        this.is_unique = source["is_unique"];
+	        this.is_primary = source["is_primary"];
+	        this.type = source["type"];
+	    }
+	}
+	export class TableStructure {
+	    table_name: string;
+	    schema?: string;
+	    columns: TableColumn[];
+	    indexes?: TableIndex[];
+	    foreign_keys?: ForeignKey[];
+	
+	    static createFrom(source: any = {}) {
+	        return new TableStructure(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.table_name = source["table_name"];
+	        this.schema = source["schema"];
+	        this.columns = this.convertValues(source["columns"], TableColumn);
+	        this.indexes = this.convertValues(source["indexes"], TableIndex);
+	        this.foreign_keys = this.convertValues(source["foreign_keys"], ForeignKey);
+	    }
+	
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
+	export class UpdateSavedQueryRequest {
+	    name: string;
+	    description: string;
+	    sql: string;
+	    connection_id: string;
+	    tags: string;
+	
+	    static createFrom(source: any = {}) {
+	        return new UpdateSavedQueryRequest(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.name = source["name"];
+	        this.description = source["description"];
+	        this.sql = source["sql"];
+	        this.connection_id = source["connection_id"];
+	        this.tags = source["tags"];
+	    }
+	}
+	export class UserConnection {
+	    id: string;
+	    name: string;
+	    type: string;
+	    host?: string;
+	    port?: number;
+	    username?: string;
+	    password: string;
+	    database: string;
+	    ssl_mode?: string;
+	    timeout: number;
+	    // Go type: time
+	    created_at: any;
+	    // Go type: time
+	    updated_at: any;
+	
+	    static createFrom(source: any = {}) {
+	        return new UserConnection(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.id = source["id"];
+	        this.name = source["name"];
+	        this.type = source["type"];
+	        this.host = source["host"];
+	        this.port = source["port"];
+	        this.username = source["username"];
+	        this.password = source["password"];
+	        this.database = source["database"];
+	        this.ssl_mode = source["ssl_mode"];
+	        this.timeout = source["timeout"];
+	        this.created_at = this.convertValues(source["created_at"], null);
+	        this.updated_at = this.convertValues(source["updated_at"], null);
+	    }
+	
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
+
+}
+
+export namespace services {
+	
+	export class ConnectionService {
+	
+	
+	    static createFrom(source: any = {}) {
+	        return new ConnectionService(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	
+	    }
+	}
+	export class QueryService {
+	
+	
+	    static createFrom(source: any = {}) {
+	        return new QueryService(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	
+	    }
+	}
+
+}
+

internal/app/app.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"context"
+	"errors"
 	"time"
 
 	"go.uber.org/zap"
@@ -13,6 +14,17 @@ import (
 	"uzdb/internal/services"
 )
 
+// rootErrMsg unwraps the full error chain and returns the deepest error message.
+func rootErrMsg(err error) string {
+	for {
+		unwrapped := errors.Unwrap(err)
+		if unwrapped == nil {
+			return err.Error()
+		}
+		err = unwrapped
+	}
+}
+
 // App is the main application structure for Wails bindings
 type App struct {
 	ctx           context.Context
@@ -124,6 +136,24 @@ func (a *App) DeleteConnection(id string) string {
 	return ""
 }
 
+// DisconnectConnection removes an active connection from the connection manager
+// Returns error message or empty string on success
+func (a *App) DisconnectConnection(id string) string {
+	if a.connectionSvc == nil {
+		return "Service not initialized"
+	}
+
+	err := a.connectionSvc.DisconnectConnection(a.ctx, id)
+	if err != nil {
+		config.GetLogger().Error("failed to disconnect connection",
+			zap.String("id", id),
+			zap.Error(err))
+		return err.Error()
+	}
+
+	return ""
+}
+
 // TestConnection tests a database connection
 // Returns (success, error_message)
 func (a *App) TestConnection(id string) (bool, string) {
@@ -137,14 +167,19 @@ func (a *App) TestConnection(id string) (bool, string) {
 		return false, err.Error()
 	}
 
-	return result.Success, result.Message
+	return result.Success, func() string {
+		if result.Success {
+			return ""
+		}
+		return result.Message
+	}()
 }
 
 // ExecuteQuery executes a SQL query on a connection
 // Returns query result or error message
 func (a *App) ExecuteQuery(connectionID, sql string) (*models.QueryResult, string) {
 	if a.connectionSvc == nil {
-		return nil, "Service not initialized"
+		return &models.QueryResult{Success: false, Error: "Service not initialized"}, ""
 	}
 
 	result, err := a.connectionSvc.ExecuteQuery(a.ctx, connectionID, sql)
@@ -153,7 +188,7 @@ func (a *App) ExecuteQuery(connectionID, sql string) (*models.QueryResult, strin
 			zap.String("connection_id", connectionID),
 			zap.String("sql", sql),
 			zap.Error(err))
-		return nil, err.Error()
+		return &models.QueryResult{Success: false, Error: rootErrMsg(err)}, ""
 	}
 
 	return result, ""
@@ -188,7 +223,7 @@ func (a *App) GetTableData(connectionID, tableName string, limit, offset int) (*
 			zap.String("connection_id", connectionID),
 			zap.String("table", tableName),
 			zap.Error(err))
-		return nil, err.Error()
+		return nil, rootErrMsg(err)
 	}
 
 	return result, ""

internal/services/connection.go

@@ -3,6 +3,7 @@ package services
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"go.uber.org/zap"
@@ -204,6 +205,17 @@ func (s *ConnectionService) DeleteConnection(ctx context.Context, id string) err
 	return nil
 }
 
+// DisconnectConnection removes an active connection from the connection manager
+func (s *ConnectionService) DisconnectConnection(ctx context.Context, id string) error {
+	if err := s.connManager.RemoveConnection(id); err != nil {
+		return fmt.Errorf("failed to disconnect connection: %w", err)
+	}
+
+	config.GetLogger().Info("connection disconnected", zap.String("id", id))
+
+	return nil
+}
+
 // TestConnection tests a database connection
 func (s *ConnectionService) TestConnection(ctx context.Context, id string) (*models.ConnectionTestResult, error) {
 	// Get connection config
@@ -343,21 +355,35 @@ func (s *ConnectionService) GetTableData(
 		return nil, err
 	}
 
-	var query string
+	// Build a properly-quoted table reference that handles 'schema.table' notation
-	switch conn.Type {
+	tableRef := buildTableRef(conn.Type, tableName)
-	case models.ConnectionTypeMySQL:
+
-		query = fmt.Sprintf("SELECT * FROM `%s` LIMIT %d OFFSET %d", tableName, limit, offset)
+	query := fmt.Sprintf("SELECT * FROM %s LIMIT %d OFFSET %d", tableRef, limit, offset)
-	case models.ConnectionTypePostgreSQL:
-		query = fmt.Sprintf(`SELECT * FROM "%s" LIMIT %d OFFSET %d`, tableName, limit, offset)
-	case models.ConnectionTypeSQLite:
-		query = fmt.Sprintf(`SELECT * FROM "%s" LIMIT %d OFFSET %d`, tableName, limit, offset)
-	default:
-		return nil, models.ErrValidationFailed
-	}
 
 	return s.ExecuteQuery(ctx, connectionID, query)
 }
 
+// buildTableRef returns a properly-quoted table reference.
+// tableName may be plain 'table' or schema-qualified 'schema.table'.
+func buildTableRef(dbType models.ConnectionType, tableName string) string {
+	if strings.Contains(tableName, ".") {
+		parts := strings.SplitN(tableName, ".", 2)
+		schema, table := parts[0], parts[1]
+		switch dbType {
+		case models.ConnectionTypeMySQL:
+			return fmt.Sprintf("`%s`.`%s`", schema, table)
+		default:
+			return fmt.Sprintf(`"%s"."%s"`, schema, table)
+		}
+	}
+	switch dbType {
+	case models.ConnectionTypeMySQL:
+		return fmt.Sprintf("`%s`", tableName)
+	default:
+		return fmt.Sprintf(`"%s"`, tableName)
+	}
+}
+
 // GetTableStructure returns the structure of a table
 func (s *ConnectionService) GetTableStructure(ctx context.Context, connectionID, tableName string) (*models.TableStructure, error) {
 	// Get connection config