MySQL / MariaDB Production Standards

MySQL and MariaDB are powerful relationship-driven databases, but AI agents MUST adhere to these strict behavioral boundaries when executing queries, utilizing the mysql-mcp server, or generating application code.

1. Query Safety & Execution Rules

• Absolute Parameterization: You MUST ALWAYS use parameterized queries (?). Under zero circumstances are you permitted to string-interpolate or concatenate variables into a raw SQL string. This is to enforce strict SQL-injection prevention.
• Guarded Reads: Every top-level SELECT statement MUST contain a LIMIT clause unless explicitly overridden by the user. Do not execute unbounded SELECT * FROM table; queries.
• Safe Destructive Ops: DELETE and UPDATE queries MUST include a WHERE clause. Never execute these operations without a targeted identifier.
• Action Scoping: Limit operations to single-statements. Do not stack multiple statements (query1; query2;) in a single payload unless executing a batch migration.

2. Connections & Transactions

• Connection Pooling: Always assume and design for connection pooling. Code evaluating database connections should handle acquiring from and releasing to a pool, avoiding connection leaks.
• Data Mutability Scopes: Whenever executing writes spanning across multiple tables (e.g., inserts requiring foreign key links), they MUST be wrapped in a transaction block: START TRANSACTION; ... COMMIT; with robust ROLLBACK logic in the catch block.

3. Strict Schema Configurations

• Mode Enforcement: Ensure sql_mode includes STRICT_TRANS_TABLES and ONLY_FULL_GROUP_BY. AI agents must not disable these modes to bypass errors; you must rewrite your GROUP BY logic to be strictly compliant.
• Foreign Keys: Explicitly define FOREIGN KEY constraints during CREATE TABLE unless specifically orchestrating a Vitess/PlanetScale sharded environment where declarative FKs are explicitly forbidden by the user context.

4. Ecosystem & Diagnostics

• Error Handling: When intercepting connection drops or authentication failures (e.g., ER_ACCESS_DENIED_ERROR), instruct the user to verify their .env configurations (MYSQL_URL, MYSQL_HOST, etc.). Do not hallucinate database names.
• Using MCP: If the mysql-mcp server is attached, prefer utilizing its formal 227+ structured tools over executing raw Bash CLI scripts (mysql -h ...) to guarantee payload optimizations and schema intelligence.