feat: implement MySQL database driver and API service for schema management and data operations

backend/app/Contracts/DatabaseDriverInterface.php

@@ -22,12 +22,12 @@ interface DatabaseDriverInterface
     /**
      * Get table data.
      */
-    public function getTableData(string $table, int $limit = 100, int $offset = 0): array;
+    public function getTableData(string $table, int $limit = 100, int $offset = 0, array $filters = []): array;
 
     /**
      * Get the count of rows in a table.
      */
-    public function getTableCount(string $table): int;
+    public function getTableCount(string $table, array $filters = []): int;
 
     /**
      * Get the underlying connection instance.

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

@@ -68,15 +68,16 @@ class SchemaController extends Controller
             
             $skip = $request->get('skip', 0);
             $take = $request->get('take', 100);
+            $filters = json_decode($request->get('filters', '[]'), true);
             
-            $data = $this->databaseService->getTableData($table, $take, $skip);
+            $data = $this->databaseService->getTableData($table, $take, $skip, $filters);
             
             $response = [
                 'data' => $data,
             ];
 
             if ($request->get('requireTotalCount') === 'true') {
-                $response['totalCount'] = $this->databaseService->getTableCount($table);
+                $response['totalCount'] = $this->databaseService->getTableCount($table, $filters);
             }
 
             return Response::json($response);

backend/app/Services/Database/MySqlDriver.php

@@ -64,15 +64,68 @@ class MySqlDriver implements DatabaseDriverInterface, SchemaDiscoveryInterface
         return $this->query("DESCRIBE `{$table}`");
     }
 
-    public function getTableData(string $table, int $limit = 100, int $offset = 0): array
+    public function getTableData(string $table, int $limit = 100, int $offset = 0, array $filters = []): array
     {
-        return $this->query("SELECT * FROM `{$table}` LIMIT ? OFFSET ?", [$limit, $offset]);
+        $query = DB::connection($this->connectionName)->table($table);
+        $this->applyFilters($query, $filters);
+        return $query->limit($limit)->offset($offset)->get()->all();
     }
 
-    public function getTableCount(string $table): int
+    public function getTableCount(string $table, array $filters = []): int
     {
-        $result = $this->query("SELECT COUNT(*) as count FROM `{$table}`");
-        return (int) ($result[0]->count ?? 0);
+        $query = DB::connection($this->connectionName)->table($table);
+        $this->applyFilters($query, $filters);
+        return $query->count();
+    }
+
+    protected function applyFilters($query, array $filters)
+    {
+        if (empty($filters)) return $query;
+
+        foreach ($filters as $filter) {
+            $field = $filter['field'] ?? ($filter['columnField'] ?? null);
+            $operator = $filter['operator'] ?? ($filter['operatorValue'] ?? null);
+            $value = $filter['value'] ?? null;
+
+            if (!$field) continue;
+
+            switch ($operator) {
+                case 'contains':
+                    $query->where($field, 'LIKE', "%{$value}%");
+                    break;
+                case 'equals':
+                case '=':
+                    $query->where($field, '=', $value);
+                    break;
+                case 'startsWith':
+                    $query->where($field, 'LIKE', "{$value}%");
+                    break;
+                case 'endsWith':
+                    $query->where($field, 'LIKE', "%{$value}");
+                    break;
+                case 'isEmpty':
+                    $query->where(function($q) use ($field) {
+                        $q->whereNull($field)->orWhere($field, '');
+                    });
+                    break;
+                case 'isNotEmpty':
+                    $query->whereNotNull($field)->where($field, '!=', '');
+                    break;
+                case 'isAnyOf':
+                    if (is_array($value)) {
+                        $query->whereIn($field, $value);
+                    }
+                    break;
+                case '>':
+                case '<':
+                case '>=':
+                case '<=':
+                case '!=':
+                    $query->where($field, $operator, $value);
+                    break;
+            }
+        }
+        return $query;
     }
 
     public function getForeignKeys(string $table): array

backend/app/Services/DatabaseService.php

@@ -78,17 +78,17 @@ class DatabaseService
     /**
      * Get table data.
      */
-    public function getTableData(string $table, int $limit = 100, int $offset = 0): array
+    public function getTableData(string $table, int $limit = 100, int $offset = 0, array $filters = []): array
     {
-        return $this->getDriver()->getTableData($table, $limit, $offset);
+        return $this->getDriver()->getTableData($table, $limit, $offset, $filters);
     }
 
     /**
      * Get table row count.
      */
-    public function getTableCount(string $table): int
+    public function getTableCount(string $table, array $filters = []): int
     {
-        return $this->getDriver()->getTableCount($table);
+        return $this->getDriver()->getTableCount($table, $filters);
     }
 
     /**