Legacy System Migration Workbench (LSMW) is a graphical tool provided by SAP R/3 for migrating data from a Legacy System into SAP. This tool is available through an SAP standard transaction code ‘LSMW’.
-The actual data upload takes place from a specific transaction depending upon the requirement such as MM01 (Create Material Master).
-The data to be uploaded is entered in a Flat File (such as a text file). This text file is uploaded into a Batch Input Structure through the interface of LSMW.
-After populating the data into the Batch Input ructure, the LSMW transaction generates a Batch Input Session with a name. The session is then executed through transaction SM35 (Batch Input: Session Overview).
-When the session is executed, the SAP standard transaction embedded in the session is simulated with the data (also embedded in the session). The transaction is then responsible for uploading the data into the SAP Database.
-This documentation has been prepared with an example of a simple transaction involving only a few screens. The LSMW interface can also be used to upload data through complex SAP transactions and requires more exploring and practice in using this tool.