Golang Database

Priority: P0 (CRITICAL)

Principles

• Prefer Raw SQL/Builders over ORMs: sqlc generates type-safe Go from SQL. ORMs (GORM) can obscure performance.
• Repository Pattern: Abstract DB access behind interfaces in internal/port/.
• Connection Pooling: Always configure pool settings.
• Transactions: ACID logic must use transactions. Pass context.Context everywhere.

Implementation Workflow

1. Choose driver — PostgreSQL: pgx/v5; MySQL: go-sql-driver/mysql; SQLite: modernc.org/sqlite.
2. Configure pool — Set MaxOpenConns, MaxIdleConns, and ConnMaxLifetime on the connection.
3. Define repository interface — Abstract DB access behind an interface at the consumer side.
4. Use context-aware queries — Always use QueryContext/ExecContext; bare queries ignore timeouts.
5. Close rows — Always defer rows.Close() and check rows.Err() after iteration.
6. Wrap in transactions — Use transactions for multi-step operations requiring atomicity.

See repository pattern and connection pool examples

Anti-Patterns

• ❌ Global var db *sql.DB — inject DB connection via constructor
• ❌ Bare Query()/Exec() without context — use QueryContext/ExecContext
• ❌ Leaked rows — always defer rows.Close() and check rows.Err()

References

• Repository Pattern Implementation
• Connection Tuning