May 2001
Intermediate to advanced
1088 pages
30h 13m
English
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Auto-Generated Keys
One of the popular ways to design tables these days is to use sequence numbers as primary key values. Some databases let you define a column as being a sequenced value. Others include special sequencer objects. Even if the database doesn't support sequences, you can still create your own sequence table to generate the key value.
The advantage of the sequence numbers is that you don't have to worry about coming up with a unique set of keys. You can't rely on people having unique first, middle, and last names, so you must come up with an additional key to distinguish people. With a sequence number, however, you have a single key column.
Note
You can only use auto-generated keys when you have a single-column key. That is, if ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.