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PostgreSQL PGCES-02 Exam - Topic 9 Question 25 Discussion

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);
A) If any row exists in the 'record' table, no change can be made to the 'master' table.
B) If 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.
C) If the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.
D) The 'record' table cannot have duplicate 'id's.
E) These SQL statements are invalid; no constraints are created.

PostgreSQL PGCES-02 Exam - Topic 9 Question 25 Discussion

Actual exam question for PostgreSQL's PGCES-02 exam
Question #: 25
Topic #: 9
[All PGCES-02 Questions]

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);

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Suggested Answer: A

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

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Mendy
8 months ago
B is too strict; you can still update master if record has an id.
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Dan
8 months ago
Wait, are these SQL statements really valid? Seems off to me.
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Rikki
9 months ago
D is not true, record can have duplicates unless specified otherwise.
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Jolene
9 months ago
I disagree, A is misleading. Changes can still be made to master.
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Mabel
9 months ago
C is correct! You can't delete from master if record has that id.
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Irving
9 months ago
I feel like option D is about uniqueness in the 'record' table, but I don't think that's what the foreign key constraint is about. I might be confused on this one!
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Leonida
9 months ago
I'm not entirely sure, but I remember something about foreign keys preventing changes to the parent table if there are dependent rows. Could that relate to option A or C?
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Daren
9 months ago
I think the foreign key constraint means that if there's a related row in the 'record' table, you can't delete the corresponding row in 'master'. So maybe it's option C?
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Micah
9 months ago
I practiced a similar question, and I think the foreign key allows for updates in 'master' as long as there are no dependent rows in 'record'. So, I might lean towards option C.
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Tawna
9 months ago
This is a good example of the kind of question I need to watch out for. It seems simple, but you have to really think about the privacy and security requirements. I'm going to mark this one as False.
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Marylyn
9 months ago
This seems simple enough. I'll just follow the instructions and double-check my work before submitting.
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Amber
10 months ago
This question seems a bit tricky. I'll need to carefully consider the differences between the production and non-production environments to determine the license cost.
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Domonique
10 months ago
"External area" doesn't seem right at all, but I'm confused between "Multiple areas" and the others. It's been a while since we reviewed these concepts!
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Valda
1 year ago
I'm just impressed they managed to fit all this into a single exam question. That's some serious database compression right there!
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Royal
1 year ago
D) The 'record' table cannot have duplicate 'id's.
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Domonique
1 year ago
C) If the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.
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Ty
1 year ago
B) If 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.
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Carri
1 year ago
C) If the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.
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Leah
1 year ago
B) If 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.
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Julie
1 year ago
A) If any row exists in the 'record' table, no change can be made to the 'master' table.
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Karma
1 year ago
A) If any row exists in the 'record' table, no change can be made to the 'master' table.
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Cammy
1 year ago
Exactly, it's a way to link the two tables together and prevent any inconsistencies.
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Tanesha
1 year ago
So, basically, the foreign key constraint ensures that you can't delete a record in the 'master' table if it's being referenced in the 'record' table.
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Latonia
1 year ago
I agree, that sounds right. It's all about maintaining data integrity.
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Fanny
1 year ago
I think the answer is C) If the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.
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Verdell
1 year ago
Option E? Really? These are perfectly valid SQL statements. Someone needs to brush up on their database knowledge.
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Avery
1 year 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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Dominic
1 year ago
C) If the 'record' table contains a row with an 'id', the corresponding 'id' row in the 'master' table cannot be deleted.
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Nickole
1 year ago
A) If any row exists in the 'record' table, no change can be made to the 'master' table.
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Dion
1 year 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
1 year 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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Gilbert
1 year ago
Hmm, that makes sense too. It's important to understand the implications of foreign key constraints in database design.
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Leonida
1 year ago
I disagree, I believe the answer is A. The foreign key constraint prevents any changes to the master table if a row exists in the record table.
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Gilbert
1 year ago
I think the answer is C. The foreign key constraint ensures that the corresponding row in the master table cannot be deleted.
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