Data Migration Basics

[Former Member]

Hi Group,

Could anybody just explain me the basic conditions for IDOCs and BAPIs for data transfer.... What i know we can use IDOCs in a distributed R/3 system... If we are transfering data from a non-sap(in case of LSMW) system then we cant use an IDOC. And what about BAPI... Can we use it for the above case.. i.e from non-sap to sap.

What are the pre-conditions for IDOCs and BAPIs to choose for a data transfer???

Thanks.

[Former Member]

Hi Samir,

Usually the data is extracted from the legacy system to a flat file or spreadsheet. Once you have this data, you could use LSMW to import it using the various input methods including both IDOC and BAPI. The process would resemble something like: Flat File - > LSMW (map, upload, and convert) -> Create IDOC -> Process IDOC).

Generally it is best to use standard SAP functionality (IDOC, BAPI, Direct Input), and the last resort is to use a custom recording. This is because standard SAP does all the checks and validation, and provides logging output (eg. IDOC).

[Former Member]

Samir

Regarding IDOC's u r absolutly correct

where as for BAPI's

BAPIs are normally called synchronously in order to get feedback immediately.A synchronous call will only work if the system we want to access is up and running.For some purposes like data transfer, SAP wanted BAPIs to invoke asynchronously so that the calling application could proceed even if the remote system was currently unavailable.

Hence these BAPIs are linked to ALE (Application Linking and Enabling),an asynchronous message passing mechanism with guaranteed delivery.ALE uses Idocs as the containers for messages. Idocs are instances of Idocs types, which in turn are associated ALE message types.

SAP has provided a generator which takes a BAPI and generates an appropriate ALE message type and an associated Idoc type.

For our data transfer purposes using LSMW, we can use only those BAPIs which are linked to the ALE message types.

I think i cleared ur point....

~~Guduri