modified: backend/.env.example

new file:   backend/src/controllers/sqlInterfaceController.ts
	new file:   backend/src/routes/sqlInterface.ts
	modified:   backend/src/server.ts
	modified:   docker-compose.external-db.yml
	modified:   frontend/src/App.tsx
	modified:   frontend/src/components/Sidebar.tsx
	new file:   frontend/src/pages/SqlInterface.tsx
	modified:   frontend/src/services/api.ts

backend/src/controllers/sqlInterfaceController.ts

@@ -0,0 +1,46 @@
+import { Request, Response } from 'express';
+import { databasePoolManager } from '../services/DatabasePoolManager';
+
+export const executeQuery = async (req: Request, res: Response) => {
+  try {
+    const { database_id, query } = req.body;
+
+    if (!database_id) {
+      return res.status(400).json({ error: 'Database ID is required' });
+    }
+
+    if (!query || typeof query !== 'string' || query.trim() === '') {
+      return res.status(400).json({ error: 'Query is required' });
+    }
+
+    const pool = databasePoolManager.getPool(database_id);
+    if (!pool) {
+      return res.status(404).json({ error: 'Database not found or not active' });
+    }
+
+    const startTime = Date.now();
+    const result = await pool.query(query);
+    const executionTime = Date.now() - startTime;
+
+    res.json({
+      success: true,
+      data: result.rows,
+      rowCount: result.rowCount,
+      fields: result.fields?.map(f => ({
+        name: f.name,
+        dataTypeID: f.dataTypeID,
+      })),
+      executionTime,
+      command: result.command,
+    });
+  } catch (error: any) {
+    console.error('SQL execution error:', error);
+    res.status(400).json({
+      success: false,
+      error: error.message || 'Query execution failed',
+      position: error.position,
+      detail: error.detail,
+      hint: error.hint,
+    });
+  }
+};