What is a lookup table?

Question

I just gave a database diagram for a DB I created to our head database person and she put a bunch of notes on it suggesting that I rename certain tables so it is clear they are

Answer 1

One use of lookup table is to store otherwise enum values.

Say, we have a Status enum.

Instead of saving "Not Started", "In Progress", "Completed", "Sent Back"... in every record in the database, we are saving integer 1, 2, ... only.

In the programming side, the ORM like Entity Framework can easily convert an underlying integer into an Enum Type.

In this way, the drawback is the integer value is not readable from the database side. In solving this problem, we add a Lookup Table like

Id   Status
1    Not Started
2    In Progress
...

So that our DBA can have a dictionary to "lookup", showing the status text by joining with this lookup table.