SQL Database - Help studying for Test

[Aylee]

Group of us have a big Database test coming up tomorrow. Our teacher is shit and doesn't like to explain anything, help, or provide us answers to any of the study guides. So figured I would post the questions were are not sure about and see if you guys can help us out. Also please provide explanation of why the provided answer is correct.

First up:

[octopus]

I think all of them are wrong ;o When you add a foreign key the syntax should be:

ALTER TABLE <table_name>
ADD CONSTRAINT <constraint_name>
FOREIGN KEY (<column_name>)
REFERENCES <table_name> (<column_name>);

A self referencing foreign key just means the referencing table name and your "alter table name" is the same. The syntax in all 4 choices are wrong, however.

[Aylee]

I think all of them are wrong ;o When you add a foreign key the syntax should be:

ALTER TABLE <table_name>
ADD CONSTRAINT <constraint_name>
FOREIGN KEY (<column_name>)
REFERENCES <table_name> (<column_name>);

A self referencing foreign key just means the referencing table name and your "alter table name" is the same. The syntax in all 4 choices are wrong, however.

LoL this is what we have to deal with on a daily basis. We have ruled out C since that just adds a new attribute and references nothing. We are thinking A. It creates a new a attribute called superviedBy then make it reference StaffNo from staff. B didnt make much since to us because your setting a foreign key to the primary key of a table? which seems pointless and I'm not even sure you can do that. But then again we have basically thought ourselves this shit...

[Bardicrune]

But then again we have basically thought ourselves this shit...

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