Answer
A foreign key is a column that references a primary key in another table, enforcing referential integrity between related tables.
Quick Answer
Foreign key links one table to another, enforcing referential integrity. The FK column in the child table must match a value in the referenced (parent) table's primary/unique key or be NULL. InnoDB enforces FK constraints on INSERT, UPDATE, and DELETE. ON DELETE CASCADE, ON DELETE SET NULL, or ON DELETE RESTRICT control behavior when the parent row is deleted.
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SugharaIQ Editorial Team
Verified Answer
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Source: SugharaIQ