PostgreSQL Exam PGCES-02 Topic 9 Question 25 Discussion

Actual exam question for PostgreSQL's PGCES-02 exam

Question #: 25
Topic #: 9

A table is defined as below. Select the most suitable description about the foreign key constraint. CREATE TABLE master (id INTEGER PRIMARY KEY, name TEXT); CREATE TABLE record (id INTEGER REFERENCES master (id), count INTEGER);

AIf any row exists in the 'record' table, no change can be made to the 'master' table.

BIf the 'record' table contains a row with an 'id', no change can be made at all to the corresponding 'id' row in the 'master' table.

CIf the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.

DThe 'record' table cannot have duplicate 'id's.

EThese SQL statements are invalid; no constraints are created.

Show Suggested Answer

Suggested Answer: A

by Veronika at May 07, 2022, 02:41 AM

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Avery

2 hours ago

Haha, good thing the 'record' table doesn't have a column called 'count_of_beers'. That would be a whole different kind of foreign key constraint!

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Dion

4 days ago

I agree with Stephane. This is a classic example of a foreign key constraint, which prevents orphaned records in the dependent table.

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Stephane

5 days ago

Option C is the correct answer. The foreign key constraint ensures that the corresponding row in the master table cannot be deleted if there is a reference to it in the record table.

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