Re: Migrating from Hierarchial DB model to RDBMS OR ?
Date: Mon, 16 May 2016 22:53:35 -0700 (PDT)
Message-ID: <4f6f4afb-18a0-4ee1-a362-686418b439cd_at_googlegroups.com>
> On Sunday, 8 May 2016 19:23:15 UTC+10, vldm10 wrote:
>
> Hi
> You can try to use Joe Celko's "Trees and Hierarchies in SQL for Smarties".
> I have not read this book, but I know that in this book are the following topics:
> - Hierarchical Database Systems and IMS.
> - Trees
> - SQL solutions for these databases
Giri
Don't use Celko's books or methods. As proved in these pages, several times, he is totally ignorant re:
• the Relational Model
• Hierarchies in the data
Lousy product, great marketing, just like Oracle.
The methods in that book create monstrosities with massive duplication, which are hard to change.
If you implement data hierarchies using the RM, and you have the hierarchies defined correctly, there will be zero duplication, and the hierarchy (yes, the structure) will be easy to change, eg. to move an entire branch of a tree, update just one row.
If you need help, write me an email. I have tutorials and sample code for the implementation (not for the translation of the model, which is education).
Cheers
Derek
Received on Tue May 17 2016 - 07:53:35 CEST