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Issue 3.6


DTM Data Generator

Issue: 3.6 (July/August 2005)
Author: Norman Palardy
Article Description: No description available.
Article Length (in bytes): 3,982
Starting Page Number: 9
Article Number: 3605
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Full text of article...

At first glance DTM Data Generator from SQLEdit seems to be a very useful tool, and the online descriptions make it sound like a fantastic tool for generating test data for database systems. Starting DTM brings up the Project Wizard and you can immediately start creating sets of rules for creating sample data for testing your database, and systems that use that data.

It offers to automate an immensely tedious job of creating test data sets.

The user interface is a bit hard to understand at first, and the online help is not particularly helpful. But, a bit of spelunking about reveals some really useful things. The basic steps are to create a set of rules for generating your sample data, and maybe tables and other objects like views, save this as a project, and execute the project steps.

You can reorder the project steps, and you can create steps that execute before the entire project and after the entire project runs. Each step can have a before and after part to it as well.

There are lots of options for generating the data that will be placed in each table. These include lookup lists, flat files, lists of values that are part of DTM, and several others, including using foreign keys from master tables which I never got to work.

Each project has a number of settings as well for controlling things like whether the generated SQL is kept in a file, whether the database schema has to be verified before running the project, and whether the project actually makes live changes to the database or not.

But, the UI is sufficiently hard to grasp that it's not obvious how you assign different data generation schemes to each column in a table. I looked in the online help for quite some time before I just started clicking randomly and discovered that the dialog would change as I selected each column in the table and then allow me to assign a different data generation scheme.

As well, in the demo I looked at, each time I ran the project I would repeatedly get errors about only generating 10 rows per table. This was despite setting the number of rows to generate for each table to 1.

DTM Data Generator also claims to support referential integrity for tables and generate sample data that meets these criteria. However, at no time did it generate data that fit the referential constraints of the Access database I worked from. This seems to be because it did not read the relationships from my Access database. Access showed all my relationships properly but they never showed up in DTM Data Generator and so the data never fit my constraints. This was a big let down as automatically generating data sets that fit referential constraints for testing purposes would be very useful.

All in all a very useful concept that just doesn't work as well as I'd hoped.

End of article.