bosskuai-database-engineeringlisted

# BosskuAI Database Engineering Use this skill when schema, query behavior, indexes, migrations, data consistency, or database choice affects the outcome. ## Database coverage - MariaDB / MySQL: InnoDB constraints, indexes, generated columns, JSON tradeoffs, online migration risk, replication-aware changes. - PostgreSQL: constraints, partial indexes, JSONB, GIN/GiST, CTEs, advisory locks, `EXPLAIN ANALYZE`. - SQLite: local/dev/test constraints, WAL mode, type affinity, concurrency limits, migration compatibility. - MongoDB: document shape, compound indexes, aggregation pipelines, schema validation, write concern, and bounded document growth. ## Review checklist - Data model matches the business invariant, not only the current UI. - Constraints exist in the database for rules that must never be violated. - Indexes match real `WHERE`, `JOIN`, `ORDER BY`, and uniqueness paths. - Migrations are reversible or have a safe forward-only rollback plan. - High-volume changes are chunked and safe for production traffic. - Query plans are checked before claiming a query is fast. - Soft deletes, tenancy, status transitions, and audit trails are modeled explicitly. ## Guardrails - Do not solve missing constraints only in application code. - Do not add indexes blindly; check selectivity and write cost. - Do not use MongoDB as a shortcut for unclear relational modeling. - Do not assume MySQL, MariaDB, PostgreSQL, and SQLite support the same DDL. ## Output format ```text Database eng