foreign key

/FOR-in kee/ · noun · Development · Origin: 1970

Definitions

  1. A column or set of columns in one table that references the primary key of another table, establishing a link between the two. Foreign keys enforce referential integrity — the database will reject operations that would create orphan records pointing to non-existent parents. They're the relational in relational database.

    In plain English: A column in a database table that points to a record in another table, like a link that ensures you can't reference something that doesn't exist.

    Example: The migration failed because you can't add a foreign key to orders.customer_id when there are already orders referencing customer IDs that no longer exist.

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