January 2012
Intermediate to advanced
296 pages
5h 4m
English
Content preview from Joe Celko's Trees and Hierarchies in SQL for Smarties, 2nd EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 15. Hierarchical Database Systems (IMS)
IMS from IBM is the one hierarchical database management system still in wide use today. It is stable, well defined, scalable, and very fast for what it does. In fact, there is a good chance that IMS databases still hold more data than SQL databases.
Keywords: DL/I, control blocks, data communications component, application programs, database record, segment, sequence field, data field
I am going to assume that most of the readers of this book have only worked with SQL. If you have heard of a Hierarchical Database System, it was mentioned in a database course in college and then forgotten. In some ways, that is too bad. It helps to know how earlier tools worked so that you can see how new tools evolved ...
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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.