When you generate the table maintenance (SE56) the system creates a dynpro and a program (in the Function group that you insert) to allow you to update the table using the SM30 transaction.
If you link the authorization group, the system checks that you are authorized to display or update that table data.
For example, if you create the authorization group ZGPF the system authomatically make the following check
AUTHORITY-CHECK OBJECT ‘S_TABU_DIS’
ID ‘DICBERCLS’ FIELD ‘ZGPF’
ID ‘ACTVT’ FIELD ’02′.
The field actvt is 01 to create, 02 to update, 03 to display data.
All user that will be able to update data will have to have “S_TABU_DIS” “ZGPF” “02″ in their user authorization.
If you link authorization &NC& to the table, there won’t be any checks. Obviously the system checks that you are authorized to SM30 transaction.
The transaction to create authorization group is SE54.
I hope to be clear … for any other question don’t hesitate to contact me!