CHECK Constraint

A constraint requiring inserted or updated rows to satisfy a search condition.

What does CHECK Constraint do in a relational database?

CHECK Constraint — A constraint requiring inserted or updated rows to satisfy a search condition.

CREATE TABLE customer (
    customer_id INTEGER PRIMARY KEY,
    email CHARACTER VARYING(255) NOT NULL,
    status CHARACTER VARYING(20) DEFAULT 'active'
);

Level: Novice · More Database terms at this level

Updated September 27, 2026