1. IF NOT ITAB INITAL
It is used for checking whether Internal table has any value in it before it process the other statments after that ...
2.
Occurs statament mean the structure is a internal table:
DATA: BEGIN OF LT_ITAB,
END OF LT_ITAB.
This is a flat structure
DATA: BEGIN OF LT_ITAB OCCURS <n>,
END OF LT_ITAB.
This is an internal table
The number <N> indicate how many lines has to have the table in initialization time: i.e. when the program is loaded in memory, the space for the table depends on the initialization numbers of the records.
AT run time if the table needs more space, this'll automatically be enhanced.
But If you know your table can have a certain numbers of records, you can indicate it in the defination, what'll improve the performance:
all the space the table needs is taken at the beginin, so it doesn't need to enhance the space at run time.
3. WITH HEADER LINE
WITH HEADER LINE creates a field with the same name as the internal table and the same type as the line type of the internal table.
Meaning it creates a work area of the line type of the internal table..
Example
-
DATA: ITAB LIKE MARA WITH HEADER LINE.
**Now you can use ITAB as a structure also..
**meaning.
ITAB-MATNR = 'ABCD'.
IF ITAB-MATNR = 'ABCD'.
ENDIF.
If you don't give header line..then the workarea is not created..
Example
-
DATA: ITAB LIKE MARA OCCURS 0.
DATA: WA LIKE ITAB.
To access the data you have to create another workarea ..
READ TABLE ITAB INTO WA INDEX 1.
IF WA-MATNR = 'ABCD'.
...
ENDIF.
Message was edited by:
Santosh Kumar Patha
Bluesky
