During data transfer into the SAP System, data has to be extracted from the non-SAP System (source system) and made available in a file (source file). The data transfer is executed using a data transfer interface (program, BAPI, or function module), which requires the data in a file (target file). The structure of this target file (target structure) depends on the transfer object.

The data or files from the source system do not usually have the required structure. One of the major tasks in data transfer is mapping (converting) the data from the source system to the required target system. The source fields have to be assigned to the target fields and the field contents may have to be adjusted (formatted).

The data transfer conversion assistant supports you when establishing the conversion rules.

The Data Transfer Workbench (DX Workbench) is used to execute the data transfer. The Legacy System Migration Workbench (LSMW) enables the source file to be converted into the target file. You have to specify conversion rules in the LSMW for this purpose. The main task is establishing the conversion rules and mapping the source structures to the target structures. The relationship between the source fields and the target fields can be 1 to 0, or 1 to 1, or 1 to n and n to m.

In Customizing, SAP Systems are configured to meet the requirements of the application and business processes. This configuration is reflected in the data, the transaction, and in the data transfer. The data required for the data transfer is therefore different in each system. You can familiarize yourself with these Customizing settings in the transaction itself. There you can determine which data is required to create the relevant application data. This information then has to be compared with the target structure of the data transfer program, BAPI, or function module. This enables you to determine which fields are required for the data transfer and which fields exist or have to be filled in the target structure.

The conversion assistant enables you to record a transaction with a transaction recorder and to compare this recording with the target structure of the relevant data transfer program, BAPI, or function module. The result is a conversion proposal. This conversion proposal delivers all the field values entered in the transaction with the respective screen name, in a tree structure. All fields of the target structure that could be required for the data transfer are listed for each field of the transaction.

The following criteria are checked for the creation of the conversion proposal:

1. Are the field names of the target structure and the fields of the transaction the same?
2. Are the data elements of the target structure and the fields of the transaction the same?
3. Are the short texts of the field description of the target structure and the fields of the transaction the same?
4. Are the domains of the target structure and the fields of the transaction the same?

The conversion proposal can be corrected or supplemented manually. A file with the required target structure can then be created from a conversion proposal in the Data Transfer Workbench. You can then use this file with the relevant data transfer program, BAPI, or function module to test the data transfer. This enables the completeness of the filled fields or field values in the structure to be determined. The errors occurring in the test can be corrected in the conversion proposal and the test can be restarted.

This conversion proposal does not usually provide a 100% solution for the conversion rules, but rather provides support. The use of the conversion assistant does, however, facilitate the creation of the conversion rules considerably.