Tag:Introduction to Constraint Types

  • MySQL Constraint Types and Examples

    Time:2019-6-16

    constraint  Constraints ensure data integrity and consistency Constraints are classified into table-level constraints and column-level constraints. Constraint types include: NOT NULL (non-null constraints), PRIMARY KEY (primary key constraints), UNIQUE KEY (unique constraints), DEFAULT (default constraints), FOREIGN (foreign key constraints). 1. Primary key constraints PRIMARY KEY There can only be one primary key per table The […]