Why Are MySQL CHECK Constraints Ignored?

MySQL CHECK Constraints: An Ignored Feature

Adding a custom CHECK constraint to a MySQL table is inherently unsuccessful. While defining the constraint appears possible, it ultimately does nothing. This behavior stems from CHECK constraints being unsupported by MySQL storage engines up to version 5.7.

MySQL's Limited CHECK Constraint Support

As the manual states, MySQL parses CHECK constraints, but ignores them. This means any CHECK constraints defined in a table schema will not be enforced by the database.

Workarounds and Alternatives

To enforce data integrity similar to CHECK constraints, triggers can be employed. However, triggers introduce additional complexity and potential performance issues.

If CHECK constraints are essential for your application, consider switching to an open-source RDBMS that supports them, such as PostgreSQL. PostgreSQL provides robust CHECK constraint functionality and is an excellent alternative to MySQL.

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