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في هذا الدرس

explain why manual schema scripts and ddl-auto fail.

الموضوعات المخطط لها

• Code is versioned in Git, but the database lives elsewhere; they must change together.
• Manual schema.sql runs drift: dev, test, and production end up different.
• spring.jpa.hibernate.ddl-auto=update guesses changes, cannot rename or drop safely, and must not be used outside throwaway experiments.
• A migration is a small numbered SQL script, applied once, in order.
• The database remembers which ones ran.