What is Legaccy System Migration Workbench? How

Interview Questions

What is Legaccy System Migration Workbench? How it can be carried out in SAP SD?

SAP Modules questions and answers

What is Legaccy System Migration Workbench? How it can be carried out in SAP SD?

Answer1:
LSMW is widely used by EDI programmers. EDI Programmers connect the SAP system to Non SAP system. During this Data migration is a necessity. When data migrates from source to destination the destination code is differrent from the source code. So what LSMW does is
* Converts the data in to batch files
* Then converts the batch files in to source code batch files
* And then mirgates data. Standard Interfaces like BAPI or Idoc are used in this process.

Answer2:
LSMW is used for migrating data from a legacy system to SAP system, or from one SAP system to another.

Apart from standard batch/direct input and recordings, BAPI and IDocs are available as additional import methods for processing the legacy data.

The LSMW comprises the following main steps:
* Read data (legacy data in spreadsheet tables and/or sequential files).
* Convert data (from the source into the target format).
* Import data (to the database used by the R/3 application.

But, before these steps, you need to perform following steps :
* Define source structure : structure of data in the source file.
* Define target structure : structure of SAP that receives data.
* Field mapping: Mapping between the source and target structure with conversions, if any.
* Specify file: location of the source file

Of all the methods used for data migration like BDC, LSMW , Call Transaction which one is used most of the time? How is the decision made which method should be followed? What is the procedure followed for this analysis?

All the 3 methods are used to migrate data. Selection of these methods depends on the scenario, amount of data need to transfer. LSMW is a ready tool provided by SAP and you have to follow some 17 steps to migrate master data. While in BDCs Session method is the better choice because of some advantages over call transaction. But call transaction is also very useful to do immediate updation of small amout of data. (In call transaction developer has to handle errors).

Bottom line is make choice of these methods based of real time requirements.

These methods are chosen completely based on situation you are in. Direct input method is not available for all scenarios; else, they are the simplest ones. In batch input method, you need to do recording for the transaction concerned. Similarly, IDoc, and BAPI are there, and use of these need to be decided based on the requirement.

Try to go through the some material on these four methods, and implement them. You will then have a fair idea about when to use which.

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