Field symbols and READ TABLE with system code 4

Question

Hi,
I have a hashed table and I am using field symbols to point to it to retrieve the field content. I then use it in the READ TABLE statement in the following way:
Loop at x_data assign <fs>.
ASSIGN COMPONENT 'xxx' OF STRUCTURE <fs> TO <c1>.
ASSIGN COMPONENT 'xxx' OF STRUCTURE <fs> TO <c2>.
READ TABLE ZZZZ assign <fs> with table key a1 = <c1>
                                           a2 = <c2>.
If sy-subrc = 0.
endif.
I ran the debugger and I keep getting a 4. I am not able to get the value from a1 and a2 to see what it is and why it is causing a 4 sy-subrc. I know the value from the hashed table and the values c1 and c2 are the same, so the sy-subrc should be 0.
How would I read a hashed table using field symbols? I know that usig a standard table, I have to sort the table on the key fields() before I actually can do the READ TABLE using the binary search.
Please advise. Thanks
RT

Answer 1

Hai Rob
Go  through the following Code
Field-Symbols are place holders for existing fields.
A Field-Symbol does not physically reserve space for a field but points to a field, which is not known until run time of the program.
Field-Symbols are like Pointers in Programming language ‘ C ‘.
Syntax check is not effective.
Syntax :
Data : v1(4) value ‘abcd’.
Field-symbols <fs>.
Assign v1 to <fs>.
Write:/ <fs>.
DATA: BEGIN OF LINE,
COL1 TYPE I,
COL2 TYPE I,
END OF LINE.
DATA ITAB LIKE SORTED TABLE OF LINE WITH UNIQUE KEY COL1.
FIELD-SYMBOLS <FS> LIKE LINE OF ITAB.
DO 4 TIMES.
LINE-COL1 = SY-INDEX.
LINE-COL2 = SY-INDEX ** 2.
APPEND LINE TO ITAB.
ENDDO.
READ TABLE ITAB WITH TABLE KEY COL1 = 2 ASSIGNING <FS>.
<FS>-COL2 = 100.
READ TABLE ITAB WITH TABLE KEY COL1 = 3 ASSIGNING <FS>.
DELETE ITAB INDEX 3.
IF <FS> IS ASSIGNED.
WRITE '<FS> is assigned!'.
ENDIF.
LOOP AT ITAB ASSIGNING <FS>.
WRITE: / <FS>-COL1, <FS>-COL2.
ENDLOOP.
The output is:
1 1
2 100
4 16
Thanks & regards
Sreenivasulu P