switch_database
Change the active database context in SQL Server using the USE statement to execute queries against different databases.
Instructions
Switch the active database context.
Changes the current database using the USE statement. The database must
exist, be online, and not be in the blocklist (MSSQL_BLOCKED_DATABASES).
Args:
database_name: Name of the database to switch to
Returns:
Dictionary with:
- status: "switched" on success, "error" on failure
- database: The new active database name
- previous_database: The previously active database
- error: Error message if switch failedInput Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| database_name | Yes |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Implementation Reference
- src/mssql_mcp/tools/databases.py:83-149 (handler)The main handler function for the 'switch_database' tool. It is decorated with @mcp.tool(), which registers it as an MCP tool. The function validates the database name, checks if it's blocked or exists and online, switches using 'USE [db]' statement, and returns status with previous and new database names.
@mcp.tool() def switch_database(database_name: str) -> dict[str, Any]: """Switch the active database context. Changes the current database using the USE statement. The database must exist, be online, and not be in the blocklist (MSSQL_BLOCKED_DATABASES). Args: database_name: Name of the database to switch to Returns: Dictionary with: - status: "switched" on success, "error" on failure - database: The new active database name - previous_database: The previously active database - error: Error message if switch failed """ try: manager = get_connection_manager() config = manager.config blocked_databases = config.blocked_databases # Check if database is blocked if database_name.lower() in blocked_databases: return { "status": "error", "error": f"Access to database '{database_name}' is not allowed", "database": database_name, } # Get current database before switching current_db_query = "SELECT DB_NAME() AS current_database" current_db_result = manager.execute_query(current_db_query) previous_database = ( current_db_result[0]["current_database"] if current_db_result else None ) # Switch database using USE statement # Note: USE cannot be parameterized, but we validate the name exists first # by checking sys.databases check_query = "SELECT name FROM sys.databases WHERE name = %s AND state_desc = 'ONLINE'" check_result = manager.execute_query(check_query, (database_name,)) if not check_result: return { "status": "error", "error": f"Database '{database_name}' does not exist or is not online", "database": database_name, } # Execute USE statement (database name is validated, use bracket quoting for safety) use_query = f"USE [{database_name}]" manager.execute_query(use_query) # Verify the switch verify_result = manager.execute_query(current_db_query) new_database = verify_result[0]["current_database"] if verify_result else None return { "status": "switched", "database": new_database, "previous_database": previous_database, } except Exception as e: logger.error(f"Error switching database: {e}") return {"error": str(e), "database": database_name}