LSMW in SAP ABAP

LSMW means Legacy System Migration Work Bench .SAP offers the Legacy System Migration (LSM) Workbench. The LSM Workbench is a SAP tool that facilitates the process of data transfer from non-SAP system (also called Legacy system) without additional programming to do data conversion. Wecan define the rules for the conversion. The LSM Workbench then generates an ABAP program and thus supports an important step in the process of data transfer.

It is a cross-application component (CA) of the SAP R/3 System and, therefore, is independent from the platform. The tool has interfaces with the Data Transfer Center and with batch input and direct input processing in R/3. The tool can be used in each of the different R/3 releases.
By combining the Data Transfer (DX) Workbench and the Legacy System Migration (LSM) Workbench in SAP Basis component Release 4.6, SAP has made substantial progress towards tackling one of the most costly and time-consuming implementation activities - the migration of legacy systems and the data transfer from ERP systems that are being replaced.
Data migration with the DX Workbench and the LSM Workbench guarantees maximum quality and consistency of your data in the SAP business solution. When data is imported, the system performs the same checks as it does during online entry. The update in your database is performed through the Standard Batch Input Program, Standard Direct Input Program and BAPIs.
Features of LSMW:
 
Instead of individual tables or field contents, the tool transfers complete business data objects (also called object class) such as Material Master, Supplier Master data. A migration object class is a unit combined from the business point of view, which can be used to transfer the data of all the legacy systems defined in the LSMW to the R/3 System.
The migration object class comprises the R/3 structures as well as the program used for data import. The batch and direct input technique is used to ensure consistency of data. For each migration object, a batch or direct input program has to be available in the SAP R/3 System.
The LSMW main functions are :
  • Definition of the legacy system structures and fields
  • Definition of object dependencies and assignment of conversion rules
    The structure and field relationships between the legacy system and the R/3 System are defined in data mapping. The way how data is being processed during migration is determined by the conversion rules.
  • Data conversion
    From the object dependencies, the LSMW generates conversion programs that translate the legacy system data.
  • Data import
    Batch or direct input is used to import the data to the SAP R/3 System.
The additional functions of LSMW are :
  • Spreadsheet interface
    Legacy system data in spreadsheet format can be processed.
  • Host interface
    Legacy system data in a structured data format (that is, with record identifiers and correct sequence) can be processed.
  • Batch input recorder
    The LSMW allows you to use the batch input recorder (shipped with the SAP R/3 standard system) in order to create user-specific classes of migration objects.
  • Automatic check functions
    This function generates and performs value checks against check tables and fixed values specified in the Data Dictionary.

Constraints

The LSMW supports a single and complete transfer of data (initial data load) and also offers a restricted support of permanent interfaces. Thus, a periodic transfer of data is possible. It, however, does not include any functions for monitoring of permanent interfaces. The tool does not support any data export interfaces (outbound interfaces).

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