If you're asking about specific examples, this book covers a lot of common patterns I've seen over the years; maybe a good starting point: https://martinfowler

If you're asking about specific examples, this book covers a lot of common patterns I've seen over the years; maybe a good starting point: https://martinfowler.com/books/refactoringDatabases.html https://martinfowler.com/books/refactoringDatabases.html https://databaserefactoring.com/ https://databaserefactoring.com/