The Unreferenced Data Report

Unreferenced data is data that is not explicitly referenced in the Procedure Division of a program. You generally want to eliminate such data. Unreferenced data often becomes part of a program as it is evolving; you might include a dummy data item for some reason, then forget to take it out.

The Unreferenced Data report includes the following information:

• A list of the files that include unreferenced data - this can be the file on which you are running the report and any copybooks that it references.
• The line number where the unreferenced data item is
• The name of the unreferenced data item
• The definition of the data item - for example, pic x(10)

You should not, though, assume that it is safe for you to remove any data item displayed as unreferenced. You should particularly be aware of the following two cases:

• If a group is defined and only the top-level group item is referred to, any subsidiary data items are flagged as being unreferenced.
• If a group is defined and only the subsidiary data items are referred to, the top-level group item is flagged as being unreferenced.

For example, your program could contain the following group definition:

03 group-item.
	    05 elementary-item-1 pic x. 
	 05 elementary-item-2 pic xx. 
	 05 elementary-item-3 pic xxx.

If the program used the elementary-item-1, elementary-item-2, and elementary-item-3 fields, group-item would be flagged as being unreferenced (unless it was referenced explicitly elsewhere in the program). Alternatively, if the program used the group-item field, elementary-item-1, elementary-item-2, and elementary-item-3 would be flagged as unreferenced (unless they were referenced explicitly somewhere else in the program).