Change validation for table objects (internal tables) can only function successfully if you specify which line of the current table is to be compared with which line in the table from the comparison period. The Key Field function defines those fields which clearly determine a table line as key fields for the table object. This means that one table cannot contain two lines that match in all key fields.

For each current table entry, the SAP System searches in the current payroll period for a table entry with the same key fields in the comparison period and then compares all fields.