AI-Generated Summary

A foreign key is a database constraint that establishes a relationship between two tables by linking a column or set of columns in one table to the primary key of another. It ensures referential integrity, meaning the data in the foreign key column must match values in the referenced primary key column. Foreign keys enforce data consistency and prevent orphaned records by restricting actions like deletions or updates that would break the relationship. They are essential for maintaining relational database structure, enabling efficient data retrieval through joins, and supporting complex queries. Proper use of foreign keys enhances data accuracy and supports robust database design.