Codes placed in Attribute 7 of an Attribute Definition item are applied as conversions, and codes placed in Attribute 8 are applied as correlatives.
The main difference between correlatives and conversions is the way in which INFO/ACCESS applies them. The general rule is that correlatives are applied before conversions. To be more specific, correlatives are applied to data in an item immediately after it is read from a file, before it is selected or sorted (or otherwise processed). Conversions, on the other hand, are applied to literals in the command line and to data after it is processed, just before it is output in a report.
When an INFO/ACCESS statement is executed, raw data is taken from the database and any correlative code is applied to it. Resulting information is derived data. Derived data is used for these purposes:
Selecting
Sorting
Totalling
Producing control breaks
Printing (except on break lines)
Once any of the above processing is done, a conversion code can be applied, producing an external format for the data. The conversion reformats the data into a form suitable for the INFO/ACCESS report, which can either be displayed on the screen or output to the printer.
Because correlative and conversion codes are placed in the file dictionary associated with the data they affect, the stored data is not changed by any of the preceding operations. In other words, correlative and conversion codes are newly applied to the data each time an INFO/ACCESS report is generated. The figure above illustrates this sequence of operations.
See Also