Which of the following are effects of defining foreign keys in InnoDB tables without specifying either ON UPDATE or ON DELETE?

The correct answer is C. InnoDB will disallow any delete or update on the primary key on a parent record that may have. The ON UPDATE and ON DELETE parts are optional. If you omit them, InnoDB simply disallows attempts to update or delete Code values in the CountryParent table if there are CityChild records that refer to them.

MySQL Storage Engines

Question

Options

AInnoDB will disallow foreign keys without specifying either ON UPDATE or ON DELETE.
BInnoDB will disallow any delete or update on the primary key regardless if there is a
CInnoDB will disallow any delete or update on the primary key on a parent record that may have
DInnoDB will allow both deletes and updates on the primary key on a parent record even if they

How the community answered

(30 responses)

A
10% (3)
B
3% (1)
C
80% (24)
D
7% (2)

Explanation

The ON UPDATE and ON DELETE parts are optional. If you omit them, InnoDB simply disallows attempts to update or delete Code values in the CountryParent table if there are CityChild records that refer to them.

Topics

#foreign keys#InnoDB#referential integrity#ON DELETE/ON UPDATE

Community Discussion

No community discussion yet for this question.

Full 1Z0-873 Practice