My Fault

When designing my first several databases, I asked the client if any field, item or bit of information about the data in the table was ever going to be unique, unchanging and always populated.

In my youthful foolishness, I believed these heads of industry when they said SSNs, Account Numbers, License numbers. I believed any silly thing that came out of their mouths was actually TRUE.

So you guys (others at this site) have been going in and cleaning up behind me if I didn't stay long enough. Sorry. If I did stay long enough, I found that EVERY SINGLE TIME THEY WERE WRONG. SSNs can be and are reused. People even STEAL them. Some people do not have SSNs. Every single account number, license number, etc. HAS AN EXCEPTION.

So, if I have learned anything, non-database programmers have absolutely no idea the importance of a primary key in a table.

Put one in every table (that holds anything interesting) as a mater of habit. It will save your butt in the long run.