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by sseagull
916 days ago
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Foreign keys are really just constraints - the row referred to by the FK must exist, and the database will ensure that. That is the basic idea. Cascading, etc are just useful features on top. While FKs and JOINs often go hand in hand, JOINs actually do not require foreign keys or any other constraint. You can join any table and column that you want regardless of FK or index or whatever (although you have to be careful about performance). |
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