Re: relational database

Hi, David:

The IBM System/38 was one of the first systems to offer a commercially available "relational database" capability, built-in. This was still fairly "early days" of commercial relational database systems, and SQL was still evolving, so there was not ANSI standard for SQL yet.

To help make the System/38 more "palatable" to the target market (IBM System/3, System/32 and System/34 customers), IBM disguised this relational database, by calling a table a FILE and a view a LOGICAL FILE, and added the ability to access the data from 3GL languages like RPG and COBOL, (so-called Record Level Access or RLA), so that those customers could migrate their programming skills and applications to a new System/38 without requiring major redesign or significant rewrites.

Just because your data is stored in a relational database management system (RDBMS) does not mean your database tables are "relational" -- even if you use SQL DDL to define them, you could still design them like "flat files" (so-called First Normal Form or 1NF) or worse.

If you have designed your database with good, modern, relational design practices (at least Third Normal Form, perhaps using ER diagrams, etc.) then it does not really matter very much if you implement that database using DDS or DDL, unless you need some of the new data types or other features that have been added only in SQL DDL in recent years.

Does that help?

Mark S. Waterbury

> On 2/8/2011 8:14 AM, David FOXWELL wrote:

Hi,

In the Redbook Stored Procedures, Triggers, and User-Defined Functions on DB2 Universal Database for iSeries,

I read : Several years ago a survey pointed out that a significant percentage of iSeries server customers did not even know that all of their business data is stored in a relational database.

I am one of those customers, I guess. Can someone point out to me how is it that my database is relational? I use only DDS.

Thanks