In this article we will be taking a brief look on Work Areas and Internal Tables in ABAP, SAP.
Work Area: A Work Area is a structure which can hold single record at a time in the ABAP Program. It is very useful for any change in internal tables or database tables.
Syntax 1:
<WORK_AREA> TYPE <Z_TABLE> .
Syntax 2:
<WORK_AREA> LIKE <T_TABLE>.
WORK_AREA is name of work area.
Z_TABLE is name of database table which is defined in ABAP Dictionary.
T_TABLE is name of structure which is defined in ABAP Program.
Internal Table: An Internal Table is a table which can hold multiple records in the ABAP Program.
Syntax 1:
<ITAB> TYPE <Z_TABLE> OCCURS n.
Syntax 2:
<ITAB> TYPE <T_TABLE> OCCURS n.
ITAB is name of Internal Table.
Z_TABLE is name of database table which is defined in ABAP Dictionary.
T_TABLE is name of structure which is defined in ABAP Program.
Difference between TYPE and LIKE:
| TYPE | LIKE |
| By using TYPE, it allocates memory to internal table or work area at runtime or at the time of execution. | By using LIKE, it allocates memory to internal table or work area immediately in the Program. |
| Refers to User Defined Data Types. | Refers to existing Data Type of Data Object. |
| Assign Data Type Directly to data object. | Assign Data Type indirectly to data object. |
Various Methods of Declaring Work Area and Internal Table
Using LIKE
DATA: BEGIN OF T_BILL, INCLUDE STRUCTURE ZBILL. DATA: MATNR TYPE NUM10, MTART TYPE CHAR50, END OF T_BILL. DATA: WA_BILL LIKE T_BILL, ITAB_BILL LIKE T_BILL OCCURS 0, IT_BILL LIKE T_BILL OCCURS 0 WITH HEADER LINE.
BEGIN OF specify start of declaration and END OF specify end of declaration. T_BILL is name of structure. INCLUDE STRUCTURE is used to add structure of ABAP Dictionary Object i.e. ZBILL is a database table defined in ABAP Dictionary. By this way you can also add other fields in the structure ie. You can create a customize structure in ABAP Program
Using TYPE
DATA: WA_BILL TYPE ZBILL, ITAB_BILL TYPE ZBILL OCCURS 0, IT_BILL TYPE ZBILL OCCURS 0 WITH HEADER LINE.
In both above methods, WA_BILL is work area. ITAB_BILL and IT_BILL are internal tables where IT_BILL is also act as a work area and internal table both due to WITH HEADER LINE which defines its structure. IT_BILL is structure and IT_BILL[ ] is internal table. OCCURS 0 defines internal table contains multiple records and allocate initial memory of 8KB to internal table and it provides or allocates initially space for 0 records in the roll area but it will increases record by record. If you use OCCURS 5 instead of OCCURS 0 then it allocates initially space for 5 records and increases 5 records by 5 records but maximum limit in the roll area is 8KB.
