Answer
CHECK ensures column values follow specific rules, enforcing data integrity at the database level.
Quick Answer
CHECK constraint enforces a condition on column values: age INTEGER CHECK (age >= 0 AND age <= 150). Table-level CHECK for multi-column conditions: CHECK (end_date > start_date). Fails silently for NULL values (NULL is not checked - it passes). PostgreSQL validates CHECK on INSERT and UPDATE. NOT NULL is a special CHECK that prevents NULL. Use for business rule enforcement.
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SugharaIQ Editorial Team
Verified Answer
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Source: SugharaIQ