TechTalk: Use Data Areas Correctly

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Data areas are handy places for storing miscellaneous bits of information. Before you create a data area, however, consider creating a file of one record instead. Here are some reasons:

1. As your database changes, the information in the data area may no longer apply to all data. For example, our MAPICS database had only one "company" until recently. When we decided to add a second company, I had to replace a data area with a file of two records.

2. Data areas cannot be journaled directly. You can have your applications write user records to a journal to save data area values, but you'll still have to restore the data area values manually.

3. Data areas do not have external definitions. (You can use a file description to externally define a data area in RPG, but none of the subfields can appear in other data areas.)

Data areas also have advantages. For example:

o They are supported by CL programs.

o They consume less system re-sources than files.

I'm not saying that you should never use data areas. I am saying that there are circumstances when a file may provide better flexibility. It's something to think about.

Editor's Note: For further information about data areas, refer to "The Versatile Data Area," MC, Feb. 1993.