Customizing Includes 

A Customizing include is a structure that satisfies a special naming convention. The name of a Customizing include begins with ‘CI_’ and the include is in the customer namespace.

If enhancements are already planned in the standard using customer-specific fields, such Customizing includes are included. in the corresponding standard table or standard structure. The Customizing include (that is the definition of the structure itself) is usually first created in the customer system and filled with fields by special Customizing transactions.

Customers can thus enhance tables and structures of the standard system without themselves having to modify the table and structure definitions. This means that these enhancements will not be lost when upgrading. If a table or structure of the standard system is enhanced with customer fields using a Customizing include, these customer fields are automatically inserted in the new delivered table or structure definition during an upgrade.

If you create a Customizing include 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.

Customers can but need not create a Customizing include and fill it with fields. If there is no Customizing include, there is no error message when the table or structure including it is activated.

A Customizing include can be contained in several tables or structures, so that they remain consistent when the include is modified.

The order of the fields in the ABAP Dictionary can differ from the order of the fields in the database. Inserting fields in a Customizing include does not result in a data conversion for transparent tables containing this include (see Adjusting Database Structures). The new fields of the ABAP Dictionary table are simply appended to the database table.