Integration testing with database access exposes what unit tests miss. It binds code to the real data layer, not an in-memory mock. Each test runs against the same schema, indexes, and constraints the production system uses. This is where you catch slow queries, deadlocks, and transaction edge cases before they hit customers.
To perform integration testing with database access, set up an isolated test database. Use migrations to create the schema. Seed it with minimal, realistic data. Run tests in transactions and roll them back after each case to keep the state clean. Containerization makes this faster—spin up a disposable database instance for each run.
Choose a strategy for connections. Open a fresh connection per test process to avoid locking issues. Keep test credentials separate from development and production, and close all connections at the end. Monitor query performance even in tests; slow queries in test environments often get worse in production.