Append
Structures
Append structures are used for enhancements that are not included in the standard. This includes special developments, country versions and adding customer fields to any tables or structures.
An append structure is a structure that is assigned to exactly one table or structure. There can be more than one append structure for a table or structure.
The following enhancements can be made to a table or structure TAB with an append structure:
· Insert new fields in TAB,
· Define foreign keys for fields of TAB that already exist,
· Attach search helps to fields of TAB that already exist,
These enhancements are part of the append structure, i.e. they must always be changed and transported with the append structure.
When a table or structure is activated, all the append structures of the table are searched and the fields of these append structures are added to the table or structure. Foreign keys and search help attachments added using the append structure are also added to the table. If an append structure is created or changed, the table or structure assigned to it is also adjusted to these changes when the append structure is activated.
Since the order of the fields in the ABAP Dictionary can differ from the order of the fields on the database, adding append structures or inserting fields in such append structures does not result in a table conversion.
The customer creates append structures in the customer namespace. The append structure is thus protected against overwriting during an upgrade. The fields in the append structure should also reside in the customer namespace, that is the field names should begin with ZZ or YY. This prevents name conflicts with fields inserted in the table by SAP.
If you create an
append structure for a table or structure, only those enhancements are allowed
that are consistent with the enhancement category of the enhanced table or
structure. For more information, see
Structure
Enhancements.
The new versions of the standard tables are imported after an upgrade, and the fields, foreign key definitions and search help attachments contained in the append structures are added to the new standard tables at activation.
A standard table contains the fields Field 1, Field 2 and Field 3. An append structure containing the fields ZZA and ZZB is defined for this table. After activating the table, the corresponding database table contains fields Field 1, Field 2, Field 3, ZZA and ZZB.
Further Remarks:
· An append structure can only be assigned to exactly one table or structure. If you want to append the same fields to several tables or structures, you can store these fields in an include structure. In this case you must create an append structure for each of these tables or structures and include the include structure there.
·
Adding an append
structure to an SAP standard table is supported by the
Modification
Assistant.
· If you want to insert a field that is to be delivered with the standard in the next Release in the customer system in advance, you must include it in the table itself as a repair. If you include such a field in an append structure for the table, it will occur twice when the new standard table is imported. This will result in an activation error.
· No append structures may be added to tables with long fields (data types VARC, LCHR or LRAW). This is because a long field must always be the last field in the table. However, structures with long fields can be enhanced with append structures.
· If a table or structure with an append structure is copied, the fields of the append structure become fields of the target table. Foreign key definitions and search help attachments appended with the append structure are copied to the target table.
· Foreign keys for the appended fields must be defined within the append structure. Fields of the table or structure assigned to the append structure may be defined when assigning the key field and foreign key field.
· Indexes on the appended fields must be defined in the original table.
· A table or structure TAB can only be enhanced with new foreign keys or search help attachments using an append structure. You therefore cannot change an existing foreign key definition or search help attachment for a field of TAB with the append structure.
See also: