SQL with database/sql

Canonical guidance

• use QueryContext, ExecContext, and BeginTx
• close rows promptly and check rows.Err()
• keep transactions as small as the unit of work allows

Use when

• standard SQL backends
• connection pooling via sql.DB
• request-scoped queries and transactions

Avoid

• context-free database calls in request paths
• forgetting to close Rows
• giant transactions around unrelated work

Preferred pattern

rows, err := db.QueryContext(ctx, q, accountID)
if err != nil {
	return err
}
defer rows.Close()

for rows.Next() {
	// scan rows
}
return rows.Err()

Anti-pattern

• opening transactions far above the boundary that knows the actual unit of work

Explanation: This anti-pattern is tempting because it centralizes setup, but it holds locks and resources longer than necessary.

Why

• database/sql works well when lifetime, context, and transaction scope stay explicit