Re: test

[Rick James]

Let's take one piece:
"Every employee works for one and only one department."
That is a "many to one" relationship. Many employees work for one department. The reasonable way to represent that is (assuming you have Employee and Department tables) to have the dept_id in the Employee table.

See how far you can get with that principle.

It will fall apart when you have a "many to many" relationship. In that case, you need an extra table that has effectively 2 columns -- the ids into each of the other tables.

Generally, have an "id" in each table. (That will call for a third column in the relation table I just mentioned.)

Now see how far you can get into writing CREATE TABLE statements. Once you have done that, you may be satisfied, or you may wish a more detail review than I have given you.