5 docs tagged with "constraints"

Learn how to enforce business logic using CHECK constraints and automate data entry with DEFAULT values in SQL.

Understand the advanced types of database keys. Learn about Composite Keys, Alternate Keys, and Super Keys with real-world examples.

Master the most important SQL constraints: Primary Keys and Foreign Keys. Learn how to uniquely identify rows and link tables together safely.

Learn how to enforce data integrity using SQL constraints. In-depth guide to NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, and CHECK constraints.

Learn how to use NOT NULL and UNIQUE constraints in SQL to prevent missing data and duplicate entries. Includes syntax and practical examples.