Additional Structures for Screen Fields 
Additional Structures for Screen Fields
When defining screen fields in the ABAP Screen Painter, do not specify structural data (such as the data type and length) directly when maintaining the screen. It is better to specify such data indirectly so that it is taken from the definition of objects in the Data Dictionary.
Individual fields are contained in various structures, depending on their meaning:
Such fields include, for example, the headers for single screens.
You might want a screen to include screen fields that are not yet included in a structure. If this is the case, you must create structure
Znnnn in addition to structure PSnnnn . You can then use structure Znnnn to store all of the fields that must be displayed on the screen but are not yet included in a Data Dictionary structure. The name of the corresponding structure for infotypes in the standard system is Qnnnn .
Data Dictionary structures with the name
The employee’s form of address is stored in field
P0002-ANRED with the value 1 for Mr and 2 for Ms . However, you want to be able to enter and display the terms Mr and Ms on the screen rather than their corresponding numerical values. If this is the case, you must use an additional field Q0002-ANREX .