CHAPTER 12 Hierarchical Database Systems (IMS)
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 this is too bad. It helps to know how the earlier tools worked so that you can see how the new tools evolve from the old ones.
The following material is taken from a series on IMS that appeared in www.dbazine.com. This is not going to make you an IMS programmer, but should help give you an overview. Why IMS? It is the most important prerelational technology that is still in wide use today. In fact, there is a good chance that IMS databases still hold more data than SQL databases. ...
Get Joe Celko's Trees and Hierarchies in SQL for Smarties now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
