Foreign Key
A foreign key is a column (or set of columns) that references the primary key of another table, enforcing referential integrity between related rows.
Foreign keys express relationships — an order belongs to a customer, a message to a conversation — and let the database guarantee those references stay valid. You can't insert an order for a customer that doesn't exist.
They also enable cascading behavior, such as deleting child rows when a parent is removed, and they document the data model directly in the schema.
Relational integrity through foreign keys is a major advantage of PostgreSQL over schemaless stores, where relationships must be maintained in application code.
Related terms
Foreign Key in Kolaybase
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