hi,
SAP Data Migration with LSMW
No ABAP effort are required for the SAP data migration. However, effort are required to map the data into the structure according to the pre-determined format as specified by the pre-written ABAP upload program of the LSMW.
The Legacy System Migration Workbench (LSMW) is a tool recommended by SAP that you can use to transfer data once only or periodically from legacy systems into an R/3 System.
More and more medium-sized firms are implementing SAP solutions, and many of them have their legacy data in desktop programs. In this case, the data is exported in a format that can be read by PC spreadsheet systems. As a result, the data transfer is mere child's play: Simply enter the field names in the first line of the table, and the LSM Workbench's import routine automatically generates the input file for your conversion program.
The LSM Workbench lets you check the data for migration against the current settings of your customizing. The check is performed after the data migration, but before the update in your database.
So although it was designed for uploading of legacy data it is not restricted to this use.
We use it for mass changes, i.e. uploading new/replacement data and it is great, but there are limits on its functionality, depending on the complexity of the transaction you are trying to replicate.
The SAP transaction code is 'LSMW' for SAP version 4.6x.
For those with the older SAP version (4.7 and below), the data migration programs might not have been pre-loaded.
You can download the LSMW at no cost from SAPNet under Services, SAP Methodology and Tools, category Tools.
If you are an existing SAP customer with an OSS ID, you can access the SAP Service Marketplace to download the LSWM for your Basis teams to install to your SAP system: http://service.sap.com/lsmw
The LSM Workbench carries out the following tasks:
Reads the transfer data from one or more files (for example, spreadsheets, sequential files etc.)
Converts the data from the source format into the target format
Note that with background processing, the input file must not be located in the presentation server. Access to presentation server files is only possible when you are working online.
What are the methods to migrate data from a legacy system to SAP?
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).
SO 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 scenario, 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.
Explain the exact difference between lsmw & bdc.
BDC- It is Batch data communication. Its used for data conversion from legacy system to SAP system. Only technical people can do it. Tcode is SHDB.
LSMW- It is legacy system migration workbench. Its also used for data conversion from legacy system to SAP system. But it is role of functional consultant.
There are 14 steps in LSMW. As soon as you complete the one step, automatically it will go to next step.
In general you can use LSMW. But if you want to transfer more than 40,000 data, then it is not possible in LSMW. That time you can take help of BDC.
refer to the link.
http://www.sap-img.com/sap-data-migration.htm
regards,
sreelakshmi
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