Sunday, November 28, 2010

Some random mysql pitfalls.

Constraints
Only PK, FK, Nullability, Unique are enforced in InnoDB. Check (expression) is not. So don't expect the following check constraint to help you catch any insertion/update with foo.value <= 20.



FK
both sides of your FK should have exactly the same signature. Otherwise you get errno 150, which indicates a syntax error in FK definition.

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