HI,
Unlike sorted tables, hashed tables, and key access to internal tables, which were only introduced in Release 4.0, standard tables already existed several releases previously. Defining a line type, table type, and tables without a header line have only been possible since Release 3.0. For this reason, there are certain features of standard tables that still exist for compatibility reasons.
Standard Tables Before Release 3.0
Before Release 3.0, internal tables all had header lines and a flat-structured line type. There were no independent table types. You could only create a table object using the OCCURS addition in the DATA statement, followed by a declaration of a flat structure:
DATA: BEGIN OF <itab> OCCURS <n>,
...
<fi> ...,
...
END OF <itab>.
This statement declared an internal table <itab> with the line type defined following the OCCURS addition. Furthermore, all internal tables had header lines.
The number <n> in the OCCURS addition had the same meaning as in the INITIAL SIZE addition from Release 4.0. Entering ‘0’ had the same effect as omitting the INITIAL SIZE addition. In this case, the initial size of the table is determined by the system.
The above statement is still possible in Release 4.0, and has roughly the same function as the following statements:
TYPES: BEGIN OF <itab>,
...
<fi> ...,
...
END OF <itab>.
DATA <itab> TYPE STANDARD TABLE OF <itab>
WITH NON-UNIQUE DEFAULT KEY
INITIAL SIZE <n>
WITH HEADER LINE.
In the original statement, no independent data type <itab> is created. Instead, the line type only exists as an attribute of the data object <itab>.
Click the below link for more details.
http://help.sap.com/saphelp_47x200/helpdata/en/fc/eb3646358411d1829f0000e829fbfe/content.htm
Regards,
Vara
Bluesky
