Exercise

REFERENCE a table with a FOREIGN KEY

In your database, you want the professors table to reference the universities table. You can do that by specifying a column in professors table that references a column in the universities table.

As just shown in the video, the syntax for that looks like this: 

ALTER TABLE a 
ADD CONSTRAINT a_fkey FOREIGN KEY (b_id) REFERENCES b (id);

Table a should now refer to table b, via b_id, which points to id. a_fkey is, as usual, a constraint name you can choose on your own.

Pay attention to the naming convention employed here: Usually, a foreign key referencing another primary key with name id is named x_id, where x is the name of the referencing table in the singular form.

Instructions 1/2

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Rename the university_shortname column to university_id in professors.