6.2Why Business Logic in the Database?

Advantage	Example
Atomicity	Calculate order total and update inventory in a single transaction
Consistency	Ensure constraints are enforced regardless of which application writes data
Performance	Aggregate millions of rows without transferring data to the application
Security	Application only calls procedures, never writes raw SQL

The trade-off: database logic is harder to version control, harder to test, and harder to debug than application code. This is exactly why testing it is important.