SAP ABAP

BADI:   BADI (Business Add-in) is a new SAP Object Oriented enhancement technique which is used to add our own business functionality to the exiting SAP standard functionality. A BADI can be used any number of times where as standard enhancement techniques can be used only once.

  when you working on BAPI so its importent to to handle the error and feth the values as per the requiments you can handle and caputre the errors  Application Log: Application Log provides an infrastructure for collecting messages and exceptions in a log, saving, reading and deleting logs in the database and displaying them. T-code used to application log SLG0 AND SLG1 AND SLG2

here senario badi invoice_update this badi fond mostley miro as per the requirments we can update and change your code and develop the senario as per the user requirments INVOICE_UPDATE *    DATA  :  lt_rbkp  TYPE  STANDARD  TABLE  OF  rbkp .    DATA  :  lt_rseg  TYPE  STANDARD  TABLE  OF  mrm_tab_mrmrseg . "rseg.    DATA   :  ls_rseg  TYPE  mrmrseg .    DATA  :  ls_rbkp  TYPE  rbkp .   ls_rbkp  =  s_rbkp_new .    DATA  :  lv_bldat  TYPE  ekko - aedat .    DATA  :  lv_budat  TYPE  rbkp - budat .    LOOP  AT  ti_rseg_new  INTO  ls_rseg .      SELECT  bedat        FROM  ekko        INTO  lv_bldat   ...

when used post invoice or work on miro then this program trigger for date validation here exit name LMR1M001 and function module name  EXIT_SAPLMRMP_010                   and inculde program name is ZXM08U16  business senario is when user enter posting date should not bel less the po documents date one badi found for miro INVOICE_UPDATE  but here i develop the senario customer exit BREAK rohinik . TYPES  :  BEGIN  OF  ty_ekko ,   ebeln  TYPE  ebeln ,   bedat  TYPE  bedat , END  OF  ty_ekko . DATA  :  lt_ekko  TYPE  STANDARD  TABLE  OF  ty_ekko ,       ls_ekko  TYPE  ty_ekko . READ  TABLE  e_tdrseg  INDEX  1 . SELECT  SINGLE  ebeln bedat FROM  ekko INTO  ls_ekko WHERE  ebeln  =  e_tdrseg...

Here this badi used to how to work migo data migration and help to creating magi used to save  and validation of data  MB_DOCUMENT_UPDATE method  IF_EX_MB_MIGO_BADI ~ POST_DOCUMENT .    BREAK-POINT .    IF  is_mkpf - budat < is_mkpf - BLDAT .     sy - ucomm  =  'ENT1' .      MESSAGE  'Posting Date Should Not Be Less Than Document Date'   TYPE  'E'  .      SET SCREEN  syst - dynnr .      LEAVE SCREEN .    ENDIF . endmethod .

some time vonder how to create invoice here simple example how to create invoice 

break rohinik . TYPES  :  BEGIN  OF  ty_final ,   ebeln  TYPE  ebeln ,   bedat  TYPE  ebdat , END  OF  ty_final . DATA  :  lt_final  TYPE  STANDARD  TABLE  OF  ty_final ,        ls_final  TYPE  ty_final . DATA  :  lt_mseg  TYPE  STANDARD  TABLE  OF  mseg  WITH  HEADER  LINE . SELECT  SINGLE  ebeln bedat FROM  ekko INTO  ls_final WHERE  ebeln  =  i_mseg - ebeln . IF  i_mkpf - bldat < ls_final - bedat .    PERFORM  folge_gleichsetzen ( saplv00f ) .   sy - ucomm  =  'ENT1' .    MESSAGE  'MIGO Document Date Should Not Be Less Than PO Create Date'    TYPE  'E'  .    SET  SCREEN...