Answer
A foreign key links a column to another table’s primary key to enforce referential integrity.
Quick Answer
Foreign key creates a referential integrity constraint - a column in one table must match a value in the primary key column of another table (or be NULL). Prevents orphaned records. ON DELETE/UPDATE: CASCADE (propagate change), SET NULL, SET DEFAULT, or RESTRICT (block the operation). FK lookups benefit from an index on the FK column in the child table.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
Want to bookmark, take notes, or join discussions?
Sign in to access all features and personalize your learning experience.
Source: SugharaIQ