Occurrences of an item or group can be increased or decreased. An OCCURS clause can be added or deleted. Data is lost when occurrences are decreased. When occurrences are increased, items or groups in the new data set record with no source in the old data set record are filled with the appropriate initial value.

If the size of an item or an occuring item within the group is changed, then it is possible that the generated reorganization text that is required to move the data from the old field to the new field might exceed the maximum allowable size. If this happens, the DASDL compiler issues the following error:

THIS REORGANIZATION CANNOT BE DONE
LENGTH OF TEXT REQUIRED FOR REORG EXCEEDS THE MAXIMUM

Other methods, such as using the LOADDUMP utility, can be used to accomplish this reorganization.