feat: implement database management service layer with MySQL driver and API controllers

backend/app/Contracts/DatabaseDriverInterface.php

@@ -78,4 +78,9 @@ interface DatabaseDriverInterface
      * Perform batch update on a table.
      */
     public function batchUpdate(string $table, array $changes): bool;
+
+    /**
+     * Create a new database.
+     */
+    public function createDatabase(string $name, string $charset = 'utf8mb4', string $collation = 'utf8mb4_unicode_ci'): bool;
 }

backend/app/Http/Controllers/Api/SchemaController.php

@@ -266,4 +266,25 @@ class SchemaController extends Controller
             return Response::json(['error' => $e->getMessage()], 400);
         }
     }
+
+    public function createDatabase(Request $request)
+    {
+        $request->validate([
+            'name' => 'required|string|max:64',
+            'charset' => 'nullable|string|max:32',
+            'collation' => 'nullable|string|max:64',
+        ]);
+
+        try {
+            $this->initializeDriver($request);
+            $name = $request->get('name');
+            $charset = $request->get('charset', 'utf8mb4');
+            $collation = $request->get('collation', 'utf8mb4_unicode_ci');
+
+            $this->databaseService->createDatabase($name, $charset, $collation);
+            return Response::json(['message' => "Database '{$name}' created successfully"]);
+        } catch (\Exception $e) {
+            return Response::json(['error' => $e->getMessage()], 400);
+        }
+    }
 }

backend/app/Services/Database/MySqlDriver.php

@@ -448,4 +448,10 @@ class MySqlDriver implements DatabaseDriverInterface, SchemaDiscoveryInterface
         fclose($handle);
         return $path;
     }
+
+    public function createDatabase(string $name, string $charset = 'utf8mb4', string $collation = 'utf8mb4_unicode_ci'): bool
+    {
+        DB::connection($this->connectionName)->statement("CREATE DATABASE `{$name}` CHARACTER SET {$charset} COLLATE {$collation}");
+        return true;
+    }
 }

backend/app/Services/DatabaseService.php

@@ -164,4 +164,12 @@ class DatabaseService
     {
         return $this->getDriver()->batchUpdate($table, $changes);
     }
+
+    /**
+     * Create a new database.
+     */
+    public function createDatabase(string $name, string $charset = 'utf8mb4', string $collation = 'utf8mb4_unicode_ci'): bool
+    {
+        return $this->getDriver()->createDatabase($name, $charset, $collation);
+    }
 }

backend/routes/api.php

@@ -10,6 +10,7 @@ Route::get('/user', function (Request $request) {
 
 Route::prefix('schema')->group(function () {
     Route::get('/databases', [SchemaController::class, 'databases']);
+    Route::post('/databases', [SchemaController::class, 'createDatabase']);
     Route::get('/tables/{database}', [SchemaController::class, 'tables']);
     Route::get('/metadata/{database}', [SchemaController::class, 'metadata']);
     Route::get('/metadata/{database}/tables', [SchemaController::class, 'tablesMetadata']);

frontend/src/components/Sidebar.tsx

@@ -1,8 +1,9 @@
 import React, { useEffect, useState, useMemo } from 'react';
-import { Box, List, ListItem, ListItemButton, ListItemIcon, ListItemText, Typography, Divider, CircularProgress, Stack, TextField, InputAdornment } from '@mui/material';
-import { Storage, Search, FilterList, ChevronRight, ExpandMore, TableChart, Folder } from '@mui/icons-material';
+import { Box, List, ListItem, ListItemButton, ListItemIcon, ListItemText, Typography, Divider, CircularProgress, Stack, TextField, InputAdornment, IconButton, Tooltip, Dialog, DialogTitle, DialogContent, DialogActions, Button, Alert, Snackbar, AlertTitle } from '@mui/material';
+import { Storage, Search, FilterList, ChevronRight, ExpandMore, TableChart, Folder, Add } from '@mui/icons-material';
 import { useAppStore } from '../store/useAppStore';
 import { SchemaService } from '../services/api';
+import type { MainNotification } from '../types/database';
 
 const Sidebar: React.FC = () => {
   const { activeDatabase, setActiveDatabase, setActiveTable, activeTable } = useAppStore();
@@ -16,18 +17,30 @@ const Sidebar: React.FC = () => {
 
   const [tablesLoading, setTablesLoading] = useState(false);
   
+  const [openNewDbDialog, setOpenNewDbDialog] = useState(false);
+  const [newDbName, setNewDbName] = useState('');
+  const [isCreatingDb, setIsCreatingDb] = useState(false);
+  const [notification, setNotification] = useState<MainNotification>({
+    open: false,
+    message: '',
+    title: '',
+    severity: 'success'
+  });
+
+  const fetchDatabases = async () => {
+    setLoading(true);
+    try {
+      const response = await SchemaService.getDatabases();
+      setDatabases(response.data);
+    } catch (error) {
+      console.error('Failed to fetch databases', error);
+    } finally {
+      setLoading(false);
+    }
+  };
+  
   // Fetch databases on mount
   useEffect(() => {
-    const fetchDatabases = async () => {
-      try {
-        const response = await SchemaService.getDatabases();
-        setDatabases(response.data);
-      } catch (error) {
-        console.error('Failed to fetch databases', error);
-      } finally {
-        setLoading(false);
-      }
-    };
     fetchDatabases();
   }, []);
 
@@ -86,11 +99,45 @@ const Sidebar: React.FC = () => {
     return tables.filter(table => table.toLowerCase().includes(tableSearch.toLowerCase()));
   }, [tables, tableSearch]);
 
+  const handleCreateDatabase = async () => {
+    if (!newDbName.trim()) return;
+    
+    setIsCreatingDb(true);
+    try {
+      await SchemaService.createDatabase(newDbName);
+      setNotification({
+        open: true,
+        title: 'Success',
+        message: `Database '${newDbName}' created successfully.`,
+        severity: 'success'
+      });
+      setOpenNewDbDialog(false);
+      setNewDbName('');
+      fetchDatabases();
+    } catch (error: any) {
+      setNotification({
+        open: true,
+        title: 'Error',
+        message: error.response?.data?.error || error.message,
+        severity: 'error'
+      });
+    } finally {
+      setIsCreatingDb(false);
+    }
+  };
+
   return (
     <Box sx={{ width: 280, borderRight: 1, borderColor: 'divider', display: 'flex', flexDirection: 'column', bgcolor: 'background.paper', zIndex: 10 }}>
-      <Box sx={{ p: 2, display: 'flex', alignItems: 'center', gap: 1.5 }}>
-        <Storage color="primary" sx={{ fontSize: 24 }} />
-        <Typography variant="h6" sx={{ fontWeight: 800, fontSize: '1.1rem' }}>Explorer</Typography>
+      <Box sx={{ p: 2, display: 'flex', alignItems: 'center', justifyContent: 'space-between' }}>
+        <Box sx={{ display: 'flex', alignItems: 'center', gap: 1.5 }}>
+          <Storage color="primary" sx={{ fontSize: 24 }} />
+          <Typography variant="h6" sx={{ fontWeight: 800, fontSize: '1.1rem' }}>Explorer</Typography>
+        </Box>
+        <Tooltip title="New Database">
+          <IconButton size="small" onClick={() => setOpenNewDbDialog(true)} sx={{ color: 'primary.main' }}>
+            <Add fontSize="small" />
+          </IconButton>
+        </Tooltip>
       </Box>
       
       <Box sx={{ px: 2, pb: 1 }}>
@@ -229,6 +276,55 @@ const Sidebar: React.FC = () => {
           </Typography>
         </Stack>
       </Box>
+
+      {/* New Database Dialog */}
+      <Dialog open={openNewDbDialog} onClose={() => setOpenNewDbDialog(false)} maxWidth="xs" fullWidth>
+        <DialogTitle sx={{ fontWeight: 800 }}>Create New Database</DialogTitle>
+        <DialogContent>
+          <TextField
+            autoFocus
+            margin="dense"
+            label="Database Name"
+            type="text"
+            fullWidth
+            variant="outlined"
+            value={newDbName}
+            onChange={(e) => setNewDbName(e.target.value)}
+            disabled={isCreatingDb}
+            onKeyDown={(e) => {
+              if (e.key === 'Enter') handleCreateDatabase();
+            }}
+          />
+        </DialogContent>
+        <DialogActions sx={{ p: 2, pt: 0 }}>
+          <Button onClick={() => setOpenNewDbDialog(false)} disabled={isCreatingDb}>Cancel</Button>
+          <Button 
+            onClick={handleCreateDatabase} 
+            variant="contained" 
+            disabled={isCreatingDb || !newDbName.trim()}
+          >
+            {isCreatingDb ? <CircularProgress size={24} /> : 'Create'}
+          </Button>
+        </DialogActions>
+      </Dialog>
+
+      {/* Local Notification */}
+      <Snackbar 
+        open={notification.open} 
+        autoHideDuration={4000} 
+        onClose={() => setNotification({ ...notification, open: false })}
+        anchorOrigin={{ vertical: 'bottom', horizontal: 'left' }}
+      >
+        <Alert 
+          severity={notification.severity} 
+          variant="filled" 
+          onClose={() => setNotification({ ...notification, open: false })}
+          sx={{ width: '100%', borderRadius: 2 }}
+        >
+          <AlertTitle sx={{ fontWeight: 700 }}>{notification.title}</AlertTitle>
+          {notification.message}
+        </Alert>
+      </Snackbar>
     </Box>
   );
 };

frontend/src/services/api.ts

@@ -24,6 +24,7 @@ export default api;
 
 export const SchemaService = {
   getDatabases: () => api.get('/schema/databases'),
+  createDatabase: (name: string, charset?: string, collation?: string) => api.post('/schema/databases', { name, charset, collation }),
   getTables: (db: string) => api.get(`/schema/tables/${db}`, { params: { database: db } }),
   getDatabaseMetadata: (db: string) => api.get(`/schema/metadata/${db}`, { params: { database: db } }),
   getTablesMetadata: (db: string) => api.get(`/schema/metadata/${db}/tables`, { params: { database: db } }),