Could you pls answer this

Question

What all the thing should be used in order to improve the performance and what all the thing should be avoided ?
Explain abt control brk statement ?
Could you pls give me clear explanation for CHECK,EXIT,STOP ?
In real time, what is the steps which is used for transfer data - BDC
whether call transaction,session method pls explain it
And also explain about the include statement used in BDC
Could you pls answer this

Answer 1

Hi
All this AT NEW, AT FIRST, AT END OF and AT LAST are called control break statements of Internal tables and are used to calculate the TOTALS based on sertain key fields in that internal table
FIrst to use these statements the ITAB has to be sorted by the key fields on whcih you need the SUM of the fields.
Some time you will get * when moving data from this int table to other table using these commands
so you have to use
READ TABLE ITAB INDEX SY-TABIX in AT..ENDAT..if you are using other fields between them
DATA: sflight_tab TYPE SORTED TABLE OF sflight
                  WITH UNIQUE KEY carrid connid fldate,
      sflight_wa  LIKE LINE OF sflight_tab.
SELECT *
       FROM sflight
       INTO TABLE sflight_tab.
sort sflight by carrid connid.
LOOP AT sflight_tab INTO sflight_wa.
  AT NEW connid.
    WRITE: / sflight_wa-carrid,
             sflight_wa-connid.
    ULINE.
  ENDAT.
  WRITE: / sflight_wa-fldate,
           sflight_wa-seatsocc.
  AT END OF connid.
    SUM.
    ULINE.
    WRITE: / 'Sum',
              sflight_wa-seatsocc UNDER sflight_wa-seatsocc.
    SKIP.
  ENDAT.
  AT END OF carrid.
    SUM.
    ULINE.
    WRITE: / 'Carrier Sum',
              sflight_wa-seatsocc UNDER sflight_wa-seatsocc.
    NEW-PAGE.
  ENDAT.
  AT LAST.
    SUM.
    WRITE: / 'Overall Sum',
              sflight_wa-seatsocc UNDER sflight_wa-seatsocc.
  ENDAT.
ENDLOOP.
BDC
BDC:
Batch Data Communication (BDC) is the process of transferring data from one SAP System to another SAP system or from a non-SAP system to SAP System.
Features :
BDC is an automatic procedure.
This method is used to transfer large amount of data that is available in electronic medium.
BDC can be used primarily when installing the SAP system and when transferring data from a legacy system (external system).
BDC uses normal transaction codes to transfer data.
Types of BDC :
CLASSICAL BATCH INPUT (Session Method)
CALL TRANSACTION
BATCH INPUT METHOD:
This method is also called as ‘CLASSICAL METHOD’.
Features:
Asynchronous processing.
Synchronous Processing in database update.
Transfer data for more than one transaction.
Batch input processing log will be generated.
During processing, no transaction is started until the previous transaction has been written to the database.
CALL TRANSACTION METHOD :
This is another method to transfer data from the legacy system.
Features:
Synchronous processing. The system performs a database commit immediately before and after the CALL TRANSACTION USING statement.
Updating the database can be either synchronous or asynchronous. The program specifies the update type.
Transfer data for a single transaction.
Transfers data for a sequence of dialog screens.
No batch input processing log is generated.
Differences between Call Transaction and Sessions Method:
Session method.
1) synchronous processing.
2) can tranfer large amount of data.
3) processing is slower.
4) error log is created
5) data is not updated until session is processed.
6) generally used for back ground jobs.
7) at atime we can update to more than one screens.
Call transaction.
1) asynchronous processing
2) can transfer small amount of data
3) processing is faster.
4) errors need to be handled explicitly
5) data is updated automatically
6) for background n fore ground jobs.
7) at atime we can update to a single screen.
For BDC:
http://myweb.dal.ca/hchinni/sap/bdc_home.htm
https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/bdc&
http://www.sap-img.com/abap/learning-bdc-programming.htm
http://www.sapdevelopment.co.uk/bdc/bdchome.htm
http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm
http://help.sap.com/saphelp_47x200/helpdata/en/69/c250684ba111d189750000e8322d00/frameset.htm
http://www.sapbrain.com/TUTORIALS/TECHNICAL/BDC_tutorial.html
Check these link:
http://www.sap-img.com/abap/difference-between-batch-input-and-call-transaction-in-bdc.htm
http://www.sap-img.com/abap/question-about-bdc-program.htm
http://www.itcserver.com/blog/2006/06/30/batch-input-vs-call-transaction/
http://www.planetsap.com/bdc_main_page.htm
call Transaction or session method ?
Regards
anji