Database Design: Composite key vs one column primary key

Question

A web application I am working on has encountered an unexpected \'bug\' - The database of the app has two tables (among many others) called \'States\' and \'Cities\'.

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Answer 1

Imtroduce a surrogate key. What are you going to do when area codes change numbets or get split? Using business keys as a primary key almost always is a mistake.

Your above summary is another example of why.