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Duplicates for Unique Keys

When rows are inserted into internal tables with a unique primary or secondary key, duplicates can occur with regard to one or more of these keys. Depending on whether the insertion operation is taking place as a single record operation or a set operation, the ABAP runtime environment reacts as follows in response to an attempt to insert an entry with duplicate key values:

• First, it checks whether duplicate key values would occur with regard to the primary key. The system behavior is as follows depending on the operation:

• When single rows are inserted using the variant
  
  INSERT wa INTO TABLE itab,
  
  duplicate entries with regard to the primary key are ignored and sy-subrc is set to 4. This is often used to filter out duplicates when setting up the table.

• In all other cases such as
  
  INSERT ... INTO itab INDEX idx
INSERT LINES OF (set operation)
  APPEND
COLLECT
MOVE, IMPORT, and so on (set operations)
  
  an ITAB_DUPLICATE_KEY runtime error occurs.

• Then the system checks whether duplicate key values would occur with regard to any available unique secondary keys. If so, the system behaves as follows:

• For the statements INSERT and APPEND, the system triggers an exception in the CX_SY_ITAB_DUPLICATE_KEY class if it is a single record operation.

• For all other insertion and assignment operations, particularly for all set operations, an ITAB_DUPLICATE_KEY runtime error occurs.

Other versions: 7.31 | 7.40 | 7.54