SQL | SQL Constraint | CHECK Constraint

What is Check Constraint? How to Set Constraint
A CHECK constraint is a kind of constraint that allows you to specify if a value in a column must meet a specific requirement.
The CHECK constraint uses a Boolean expression to evaluate the values before insert or update to the column. If the values pass the check,
PostgreSQL will insert or update these values into the column.You normally use the CHECK constraint at the time of creating the table using the
CREATE TABLE statement.