You’ve got an existing application with a database back end. You’re thinking about changing the database, and you don’t wanna break stuff.
The most important thing to understand is difference between constructive and destructive changes, also known as additive and destructive changes, or non-breaking and breaking changes.
Constructive change examples: adding a new table or view, adding a new nullable column to an existing table, adding a new optional parameter to an existing stored procedure or function. These changes should never be made in a way that breaks anything that queries the database.
Destructive change examples: dropping a table or