Authenticating User Login Details in SAP or Verifing Username and Password in SAP

SUSR_CHECK_LOGON_DATA  is the function module used to verify authentication 

Or 

 SUSR_LOGIN_CHECK_RFC , we can verify authentication.

New Debugger Tips and Tricks

http://scn.sap.com/community/abap/testing-and-troubleshooting/blog/2010/11/10/new-abap-debugger-tips-and-tricks

How to Avoid Internal Commit or Implicit Commit in Standard BAPI

Below is the reply from SAP to avoid internal/implicit commit in standard Bapis : BAPIs BAPI_BATCH_CREATE, BAPI_BATCH_CHANGE, and
BAPI_BATCH_SAVE_REPLICA

Not sure whether this works for other standard Bapi's or not . We can try the below method given by SAP




BAPIs BAPI_BATCH_CREATE, BAPI_BATCH_CHANGE, and
BAPI_BATCH_SAVE_REPLICA can be used for maintaining batch data.
The three BAPIs mentioned above implicitly carry out a separate COMMIT
WORK.
If a COMMIT WORK AND WAIT is required, or if batch maintenance is to
be included om a transaction, the implicit COMMIT of the BAPIs has to
be suppressed.
This is done by calling function module 'TRANSACTION_BEGIN' before
calling the individual BAPI. Thus the calling program takes over
transaction control. The transaction is terminated by calling function
18.09.2013 Page 3 of 4
SAP Note 619913 - FAQ: Basic functions of batch
management
module 'TRANSACTION_END' or 'BAPI_TRANSACTION_COMMIT'.
BAPI_BATCH_CREATE
This BAPI exclusively serves for creating new batches or expanding
existing batches by plant or storage location segments.
BAPI_BATCH_CHANGE
This BAPI exclusively serves for changing existing batches.
BAPI_BATCH_SAVE_REPLICA
This BAPI creates batches or changes existing batches. It combines the
functions of the above-mentioned BAPIs.

Changing the import parameter of User Exit

DM07M is the input parameter of a user exit. Check the image for your information .

Declare a constant with main program in bracket followed by the field you want to change.
Example  : 
Constant : gc_temp type char30 value '(Main program name) Table-field' .

Field symbol : <FS> type table-field .

assign (gc_temp) to <FS> .

move the value required to field symbol.
Move 'Bharat' to <FS> .

Below is the example


  CONSTANTS: gc_ref_fld TYPE char25 VALUE '(SAPMM07M)DM07M-KZCLA' .

FIELD-SYMBOLS: <fs_wa> TYPE dm07m-kzcla.

ASSIGN (gc_ref_fld) TO <fs_wa>.

IF <fs_wa> IS ASSIGNED.
*Do not show the characteristic screen...change to background mode
  MOVE '1' TO <fs_wa>.
ENDIF.

Wild Card Search in Select Statements

for suppose you need wild card search parameter like

data:patient(10)  type c.

search : a*

TRANSLATE  patient TO UPPER CASE.
replace all occurrences of  '*'  in patient with '%'.

select a
           b
           c
            into table itab
           where  A like patient.


With queries, I think its possible to use just the wild card '%'.
Say N%, then it retrieves data starting with N
%N% retrieves data which has N anywhere in between
%N retrieves data ending with N.

Function module to find Differnce between two timestamps in Hours and minutes

SD_CALC_DURATION_FROM_DATETIME

This function module gives the time difference between two dates and time mentioned for each date.

Function module to get Number of Days per Month

NUMBER_OF_DAYS_PER_MONTH_GET