Haroon966 Database Dev
Apply when designing or changing application database schema: models, migrations, indexes, and query performance. For data analysis, ETL, or reporting scripts, see data-engineer.
When to Use This Skill
- Schema design: tables, columns, relationships
- Migrations (creating, altering, rolling back)
- Indexes and query performance
- Data modeling and normalization
- ORM usage (e.g. Django ORM) for app data access
- Avoiding N+1 and writing efficient queries
Principles
- Migrations: Prefer reversible migrations; avoid destructive changes (drops, big alters) without backup or a clear safety path.
- Transactions: Use transactions for multi-step writes; keep them short.
- Safety: No raw DDL in production without review; test migrations on a copy of data when possible.
Patterns
- Naming: Consistent table and column names (snake_case typical); clear, descriptive names for indexes.
- Indexes: Add indexes for columns used in WHERE, JOIN, ORDER BY; avoid over-indexing; consider composite indexes for common query patterns.
- N+1: Use select_related / prefetch_related (Django) or equivalent to batch-load relations; profile before optimizing.
- Migration workflow: One logical change per migration; run migrations in order; have a rollback or forward-only strategy documented.
Conventions
- In Django projects: use Django migrations and the Django ORM; prefer parameterized queries for raw SQL; document schema changes.
- Align with backend-dev (Django) when in the same project (e.g. model placement, migration hygiene).
Distinction from data-engineer: This skill focuses on schema and migrations for the application’s database. The data-engineer skill focuses on SQL, data scripts, and analysis (local/remote DBs, ETL, reporting).