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Question

Foreign key does not depend on cardinality only  but primary key only depend on cardinality .

what does it mean please explain with example..

Comments

Foreign key does not have it's  own elements ,it contains elements of primary key where foreign key is referencing,a nd also foreign key can have null,repeated elments of primary key.

Primary key contains only unique elements ,no reparation,no null so cardinality does matter for primary key.