Question

New to Oracle SQL and I assume that this is a very straight forward question but I can’t find a direct answer. I have an employees table in my database. One of the columns is ’emp_state’ which is to show the State in which the employee resides. I also have a ‘Customer’ table and an ‘office’ table, which also both have a ‘State’ field. To reduce the amount of redundant data in my database, I have created a ‘State’ table, which will have all the states with a corresponding ID. I want to reference this table in the other tables as mentioned. When setting up my table, what should I define as the foreign key in the relevant tables? Should it be ‘State_id’ or ‘State_name’? I want the state name to appear in any queries that are run, rather than the state ID which would be meaningless to a user.

Thank you!

Answer 1

• You should use state_id. If is much faster to join on a INT then a VARCHAR.
• If you need the name if a state the you should JOIN on the table and get it
• If you are planing to update the state name then you need to update all the relate tables. If you have a id then you just need to update the name column.
• You would probably not have the same state name twice. But what if you do? Then you must change it or append some strange number on the state name.

So bottom line: Always use the id