General Syntax of a Call transaction method

Here you can find out the several parameter and their values while calling call transaction method

CALL TRANSACTION <tcode>
  MODE <mode>
  UPDATE <update>
  Where,
 <tcode>: Transaction code
 <bdc_tab>: Internal table of structure BDCDATA
 <mode>: Display mode
 <update>: Update mode


MODE parameter above is used to specify whether data transfer processing should be displayed as it happens. You can choose between three modes:

Mode	Description	Significance
A	Display all	All screens and the data that goes in them appear when you run your program
E	Display errors only	The transaction goes into display mode as soon as an error in one of the screens is detected. You can then correct the error
N	No display	All screens are processed invisibly, regardless of whether there are errors or not. Control returns to your program as soon as transaction processing is finished.

UPDATE parameter to specify how updates produced by a transaction should be processed.    
                             

Mode	Description	Significance
S	Synchronous	In this mode, the called transaction waits for any updates that it produces to be completed. The called transaction is able to return any update error message that occurs to your program.
A	Asynchronous	In this mode, the called transaction does not wait for any updates it produces to be completed. It simply passes the updates to the SAP update service.
L	Local update	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