Re: About Entity Relation Diagram

From: Mark D Powell <Mark.Powell_at_eds.com>
Date: 16 Dec 2004 05:18:21 -0800
Message-ID: <1103203101.391468.169390@f14g2000cwb.googlegroups.com>

Silver, why do you think the column list is too large. We have several tables with more than 100 columns in them. As long as each and every column is fully dependend on the PK then the data is normalized. Splitting data that shares the same PK into multiple tables is denormalized.

Now, if the combined length of the columns exceeds the maximum row length supported by your RDBMS then you will have to split the rows into pieces each of which will have to be stored in a separate table, but the tables will share the same PK. This is a case where the physical implementation has to vary from the logical design due to limitations in the software.

HTH -- Mark D Powell -- Received on Thu Dec 16 2004 - 07:18:21 CST