FACTS ON INCLUDE & APPEND Structures

Includes

With tables and structures it is possible to include the fields of another structure as well as to list the individual fields. Individual fields and includes can be combined as required.

If an include is changed, all the tables and structures that contain this include are automatically adjusted.

Example: Structure X is included in tables A and B. If another field is inserted into structure X, this field is also inserted in tables A and B.

Includes can also be nested, i.e. structure A includes structure B, which in turn includes another structure C etc. The maximum nesting depth is limited to nine. A path of nested includes in a table or structure therefore can have at most length nine (excluding the table/structure itself).

Only flat structures can be included. In a flat structure, each field either refers to a data element or is directly assigned a data type and length by direct type entry.

Only structures can be included in a table. Both tables and structures can be included in a structure, but only one table may lie on a path of nested includes.

Example: Table TAB1 includes structure STRUKT1, which in turn includes structure STRUKT2. Only table TAB1 lies on the path of nested includes. It is also possible to include TAB1 in a further structure STRUKT0, but no other table may be included in TAB1 because in this case two tables (TAB1 and TAB2) would lie on a path of nested includes.

Append Structures

Append structures are used for enhancements which are not provided for in the standard (special developments, country versions and adding customer fields to SAP standard tables).

An append structure is assigned to exactly one table. There can however be several append structures to one table. If an append structure is created or changed, the table assigned to it (appending object) is also activated again at activation and the changes also take effect there.

An append structure permits the following enhancements to a table or structure:

• Add new fields

• Add foreign keys to fields of the appending object

• Add search help attachments to fields of the appending object

Appending an append structure or inserting fields in an existing append structure does not lead to the conversion of the table. The fields of the append structure are appended to the database table.

Append structures are created by customers in the customer name range and are thus protected against overwriting in upgrades or release upgrades. After a release upgrade, the new versions of the standard tables are imported and fields contained in append structures are appended to the new standard tables.

Note: Append structures can only be created for transparent tables and structures. It is not possible to add fields with an append structure for transparent tables containing a long field. Furthermore, append structures may not be created for tables and structures of the central Basis of the R/3 System.