Wat is synchronous, asynchronous & local mode of update in BDC plz help

Question

wat is synchronous, asynchronous & local mode of update in BDC .
plz explain each of them

Answer 1

A Asynchronous updating. In this mode, the called transaction does not wait for any updates it produces to be completed( does not wait till the update in database is complete either it is successful or un successful). It simply passes the updates to the SAP update service. Asynchronous processing therefore usually results in faster execution of your data transfer program.
Asynchronous processing is NOT recommended for processing any larger amount of data. This is because the called transaction receives no completion message from the update module in asynchronous updating. The calling data transfer program, in turn, cannot determine whether a called transaction ended with a successful update of the database or not.
If you use asynchronous updating, then you will need to use the update management facility (Transaction SM12) to check whether updates have been terminated abnormally during session processing. Error analysis and recovery is less convenient than with synchronous updating.
S Synchronous updating. In this mode, the called transaction waits for any updates that it produces to be completed. Execution is slower than with asynchronous updating because called transactions wait for updating to be completed. However, the called transaction is able to return any update error message that occurs to your program. It is much easier for you to analyze and recover from errors.
L Local updating. If you update data locally, the update of the database will not be processed in a separate process, but in the process of the calling program. (See the ABAP keyword documentation on SET UPDATE TASK LOCAL for more information.)
reward if it is helpful..
sai ramesh.