feat: support clone (#136)

* feat: support clone

* Update src/connectors/interface.ts

Co-authored-by: Copilot <[email protected]>

---------

Co-authored-by: Copilot <[email protected]>

Author: tianzhou

src/connectors/interface.ts

@@ -96,8 +96,8 @@ export interface Connector {
   /** DSN parser for this connector */
   dsnParser: DSNParser;
 
-  /** Create a new instance of this connector (for multi-source support) - optional, only implemented for tested connectors */
-  clone?(): Connector;
+  /** Create a new instance of this connector (for multi-source support). This method is required for all connectors. */
+  clone(): Connector;
 
   /** Connect to the database using DSN, with optional init script and database-specific configuration */
   connect(dsn: string, initScript?: string, config?: ConnectorConfig): Promise<void>;

src/connectors/manager.ts

@@ -112,9 +112,8 @@ export class ConnectorManager {
     }
 
     // Create a new instance of the connector (clone) to avoid sharing state between sources
-    // Only SQLite currently supports cloning for multi-source configurations
-    // Other databases will reuse the singleton instance (not recommended for multi-source)
-    const connector = connectorPrototype.clone ? connectorPrototype.clone() : connectorPrototype;
+    // All connectors support cloning for multi-source configurations
+    const connector = connectorPrototype.clone();
 
     // Build config for database-specific options
     const config: ConnectorConfig = {};

src/connectors/mariadb/index.ts

@@ -98,6 +98,10 @@ export class MariaDBConnector implements Connector {
 
   private pool: mariadb.Pool | null = null;
 
+  clone(): Connector {
+    return new MariaDBConnector();
+  }
+
   async connect(dsn: string, initScript?: string, config?: ConnectorConfig): Promise<void> {
     try {
       const connectionConfig = await this.dsnParser.parse(dsn, config);

src/connectors/mysql/index.ts

@@ -101,6 +101,10 @@ export class MySQLConnector implements Connector {
 
   private pool: mysql.Pool | null = null;
 
+  clone(): Connector {
+    return new MySQLConnector();
+  }
+
   async connect(dsn: string, initScript?: string, config?: ConnectorConfig): Promise<void> {
     try {
       const connectionOptions = await this.dsnParser.parse(dsn, config);

src/connectors/sqlserver/index.ts

@@ -137,6 +137,10 @@ export class SQLServerConnector implements Connector {
   private connection?: sql.ConnectionPool;
   private config?: sql.config;
 
+  clone(): Connector {
+    return new SQLServerConnector();
+  }
+
   async connect(dsn: string, initScript?: string, config?: ConnectorConfig): Promise<void> {
     try {
       this.config = await this.dsnParser.parse(dsn, config);