Backend Queries

SQL injection is prevented by using parameterized queries, which separate SQL code from user input. This ensures malicious input cannot alter query logic. Always use parameterized queries or prepared statements when accepting user-supplied values in SELECT, INSERT, UPDATE, or DELETE operations.

N+1 problems occur when fetching a parent record triggers separate queries for each child record, drastically reducing performance. Use eager loading to fetch related data in a single query with proper joins, or leverage query caching to avoid redundant database calls.

Optimize queries by creating appropriate indexes on frequently searched columns, using joins efficiently, implementing eager loading for related data, and applying query caching where possible. These techniques reduce execution time and database load across SELECT, transaction, and data-fetching operations.

Yes, secure and performant query practices apply across SQL, ORMs, and query builders. Ensure your ORM or query builder supports parameterized queries, indexing hints, and eager loading patterns to maintain security and performance standards.

Apply secure, performant query practices to repository files, query layers, and files marked *.repository.ts. These data access layers are where SELECT queries, joins, transactions, and eager loading logic should be consistently implemented and optimized.

Indexing accelerates data retrieval by organizing table columns, reducing the rows the database must scan. Proper indexing on columns used in WHERE clauses, joins, and sorting significantly improves query execution speed and reduces backend load.