Understanding data storage

How Data is Physically Stored

Databases persist data on disk (or in memory, for caching layers) in files organized into structures like tablespaces, pages, and blocks, managed internally by the DBMS.

Logical vs Physical Storage

Users interact with data logically through tables and rows, while the DBMS handles the physical details of where and how that data is actually written to storage—abstracting this complexity away from applications.

Why Testers Should Care

Understanding that data is persisted (not just held in memory) helps testers design tests around scenarios like application crashes, restarts, or concurrent access, to confirm that committed data survives as expected.