LEGACY SYSTEM MIGRATION IN SAP.....

Step by Step Legacy System Migration Workbench - 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.

The LSM Workbench covers the following steps:-
(1) Read the legacy data from one or several files (e.g. spreadsheet tables, sequential files).
(2) Convert the data from source format to target format.
(3) Import the data using standard interfaces (Batch Input, Direct Input, BAPI, IDoc).
The Steps for LSMW are:
Example: Customer Master upload:
LSMW to Update Customer Master Records with Transaction Recording
Call Legacy System Migration Workbench by entering transaction code LSMW. Every conversion task is grouped together as Project / Subproject / Object structure. Create a Project called LSMW_DEMO and a Subproject as CUSTOMERS and Object as CUST_REC

Step 1: Maintain Object attributes:-
In this example, you will be updating the customer master records with the help of recording a transaction (XD02). Choose radio button Batch Input Recording and click on the recording overview icon to record the R/3 transaction. Enter the Recording name as XD02_REC, the description as Customer Master Updates Recording, and the transaction code as XD02.

Step 2. Maintain Source Structures:-
Give a name and a description to the source structure.

Step 3. Maintain Source Fields:-
In this step, you need to list what fields are present in the source structure. The easiest way is to click on ‘Table Maintenance’ icon to enter Fieldname, Type and Length for each field.

Step 4: Maintain Structure Relations:-
Execute a step to ‘Maintain Structure Relations’. Since, there is only one Source and Target Structure, the relationship is defaulted automatically.

Step 5: Maintain field mapping and conversion rules:-
Field RF02D-D0310 represents that you chose ‘Sales view’ for the customer Master screen accordingly its value should be set to X. Keep your cursor on field RF02D-D0310 and click on Constant rule icon to choose the constant value of ‘X’.
If your source file already has the field value, you choose rule ‘Source Field’. Keep cursor on field ‘KUNNR’ and click on ‘Assign Source field’ icon to choose source field CUSTOMER from structure XD02S

Step 6: Maintain fixed values, translations, user-defined routines:-
You can also maintain re-usable translations and user-defined routines, which can be used across conversion tasks. In this case, that step is not required.

Step 7: Specify files:-
In this step, we define how the layout of the input file is. The input file is a Tab delimited with the first row as field names. It is present on my PC (local drive) as C:\XD02.txt.

Step 8: Assign files:-
Execute step ‘Assign Files’ and the system automatically defaults the filename to the source structure.

Step 9: Read data:-
In this step, LSMW reads the data from the source file (from your PC’s local drive). You have the option to read only selected rows and convert data values to Internal format.

Step 10: Display read data:-
This step is optional. If required, you can review the field contents for the rows of data read.

Step 11: Convert data:-
This is the step that actually converts the source data (in source format) to a target format. Based on the conversion rules defined, source fields are mapped to target fields.

Step 12: Display Converted data:-
Again this is an optional step to view how the source data is converted to internal SAP format.

Step 13: Create batch input session:-
Once the source data is converted in an internal format, you can create a batch session to process updates.

Step 14: Run Batch Input Session:-
You can execute the BDC session by Run Batch input session. Executing a batch input session is a standard SM35 transaction for managing BDC sessions. Once you have successfully executed the batch input session, the customer master records are updated in the system. You can confirm this by viewing the customer master records (XD03).