Assign statement - Assign program field to field symbol

Hi,
System R/3 470
I have used the Assign statement to read variables from another program, in the current system. and everything works as expected.
I now want to read a button that is pressed from the Workflow inbox.
However when I try and read the value from the calling program SAPLSIW1 field L_FUNCTION, I get an error field symbols is not assigned
 ASSIGN '(SAPLSIW1)l_function' TO <fs_func_gl>.
 ASSIGN (<fs_func_gl>) TO <fs_func_lc>.
 IF <fs_func_lc> IS ASSIGNED.
 lwa_func = <fs_func_lc>.
 ENDIF.
I can see all the programs in the call stacks and if I navigate to the program I can see the value fro field l_fucntion
Any help will be appreciated
Thanks
J-J

Hello,
1. From your code snippet i understand that you've not use ALL CAPS in your ASSIGN command
ASSIGN '(SAPLSIW1)L_FUNCTION' TO <fs_func_gl>.
2. As mentioned by Naimesh check the "Call Stack" in debugger & see what are the fields available. If the particular field is not in the "Call Stack" you can't ASSIGN it!
BR,
Suhas

Similar Messages

Dynamic assign in field symbols

dynamic assign in field symbols

Hi,
DYNAMIC ASSIGN:
If you do not know the name of the field that you want to assign to the field symbol when you write a program, you can use a dynamic ASSIGN statement:
ASSIGN (<f>) TO <FS>.
This statement assigns the field whose name is contained in the field <f> to the field symbol <FS>. You cannot use offset and length in a dynamic ASSIGN.
At runtime, the system searches for the corresponding data object in the following order:
If the ASSIGN statement is in a procedure, the system searches first in its local data.
If it cannot find the object in the local data (or if the ASSIGN statement is not in a procedure), it then looks in the local data of the program.
If the field does not exist in the global data of the program, the system looks in the table work areas declared with the TABLES statement in the main program of the current program group. A program group consists of a main program and all of the programs that are loaded into the same internal session as a result of other program calls.
If the search is successful and a field can be assigned to the field symbol, SY-SUBRC is set to 0. Otherwise, it is set to 4, and the field symbol remains unchanged. For security reasons, you should always check the value of SY-SUBRC after a dynamic ASSIGN to prevent the field symbol pointing to the wrong area.
Searching for the field in this way slows down the program. You should therefore only use the dynamic ASSIGN statement when absolutely necessary. If you know when you create the program that you want to assign a table work area to the field symbol, you can also use the following variant of the dynamic ASSIGN statement:
ASSIGN TABLE FIELD (<f>) TO <FS>.
The system then only searches within the table work areas in the main program of the current program group for the data object that is to be assigned to the field symbol. This addition is forbidden in ABAP Objects, since the latter does not support table work areas.
Suppose we have three programs. The main program:
REPORT demo_field_symbols_dynami_as_1.
TABLES sbook.
sbook-fldate = sy-datum.
PERFORM form1 IN PROGRAM demo_form1.
The other two programs are:
REPORT demo_form1.
FORM form1.
PERFORM form2 IN PROGRAM demo_form2.
ENDFORM.
and
REPORT demo_form2.
FORM form2.
DATA name(20) TYPE c VALUE 'SBOOK-FLDATE'.
FIELD-SYMBOLS <fs> TYPE ANY.
ASSIGN (name) TO <fs>.
IF sy-subrc EQ 0.
 WRITE / <fs>.
ENDIF.
ENDFORM.
The output looks something like this:
02.06.1998
The program group in the internal session now consists of the programs DEMO, MYFORMS1 and MYFORMS2. The field symbol <FS> is defined in MYFORMS2. After the dynamic ASSIGN statement, it points to the component FLDATE of the table work area SBOOK declared in the main program DEMO.
REPORT demo_field_symbols_dynami_as_2 .
TABLES sbook.
DATA: name1(20) TYPE c VALUE 'SBOOK-FLDATE',
 name2(20) TYPE c VALUE 'NAME1'.
FIELD-SYMBOLS <fs> TYPE ANY.
ASSIGN TABLE FIELD (name1) TO <fs>.
WRITE: / 'SY-SUBRC:', sy-subrc.
ASSIGN TABLE FIELD (name2) TO <fs>.
WRITE: / 'SY-SUBRC:', sy-subrc.
The output is:
SY-SUBRC: 0
SY-SUBRC: 4
In the first ASSIGN statement, the system finds the component FLDATE of the table work area SBOOK and SY-SUBRC is set to 0. In the second ASSIGN statement, the system does not find the field NAME1 because it is declared by the DATA statement and not by the TABLES statement. In this case, SY-SUBRC is set to 4.
Reference: http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb38d5358411d1829f0000e829fbfe/content.htm
reward points if helpful.
Regards,
Ramya

Screen value not assign in field symbol

Hi gurus,
 I create a field symbol for module pool programming for assigning screen value. I create a tab in main screen and three subscreen for tab. in first screen values perfectly asign in field symbol but second subscreen FS1,FS2,FS3 values not assign.
Atthe time of save three subscreen values stored in internal table, then insert into ztable.
PERFORM SAVE_DATA USING '15' 'GTAB-IO_CODE' 'GTAB-IO_PER' 'GATB-IO_VAL'.
PERFORM SAVE_DATA USING '26' 'GTAB-IO_SCODE' 'GTAB-IO_SPER' 'GTAB-IO_SVAL'.
FORM SAVE_DATA USING X TYPE I
 FS1 TYPE STRING
 FS2 TYPE STRING
 FS3 TYPE STRING.
*FORM SAVE_DATA USING X TYPE I FS1 TYPE STRING.
CLEAR SNO.
CLEAR C.
ITAB-MANDT = SY-MANDT.
ITAB-BUKRS = '1000'.
ITAB-DOCNO = '0001000005'.
ITAB-BUDAT = SY-DATUM.
DO X TIMES.
IF X EQ '15'.
 FS1 = 'GTAB-IO_CODE'.
 FS2 = 'GTAB-IO_PER'.
 FS3 = 'GTAB-IO_VAL'.
ELSEIF X EQ '26'.
 FS1 = 'GTAB-IO_SCODE'.
 FS2 = 'GTAB-IO_SPER'.
 FS3 = 'GTAB-IO_SVAL'.
ENDIF.
 C = C + 1.
 SNO = SNO + 10.
 ITAB-SLNO = SNO.
 ZCOMRP_ORTRN-SLNO = SNO.
 CONCATENATE FS1 C INTO FS1.
 ASSIGN (FS1) TO <FS>.
 ZCOMRP_ORTRN-PRCOD = <FS>.
 ITAB-PRCOD = <FS>.
 CONCATENATE FS2 C INTO FS2.
 ASSIGN (FS2) TO <FS>.
 ZCOMRP_ORTRN-KBETR = <FS>.
 ITAB-KBETR = <FS>.
 CONCATENATE FS3 C INTO FS3.
 ASSIGN (FS3) TO <FS>.
 ZCOMRP_ORTRN-DMBTR = <FS>.
 ITAB-DMBTR = <FS>.
 INSERT ZCOMRP_ORTRN.
 APPEND ITAB.
 INSERT ZCOMRP_ORTRN FROM ITAB.
 CLEAR FS1.
 CLEAR FS2.
 CLEAR FS3.
 CLEAR C.
ENDDO.
PERFORM CLEAR.
ENDFORM. " SAVE_DATA

solved

Dump GETWA_NOT_ASSIGNED assigning a Field Symbol

i have
DATA: W_PROG3(30) VALUE '(SAPLV56U)I_XVTTK[]'.
ASSIGN (W_PROG3) TO is executed i got a dump.
Only in this case i got a dump.
I hope somebody could help me with this

Hello,
I have the same Problem with another Table. To evaluate the Problem I wrote a little testprogram with the following code:
*& Report ZL_FROELICHM_TEST1 *
report ZL_FROELICHM_TEST1 .
data: VBSK_I like VBSK.
data: T_KOMDLGN like KOMDLGN occurs 10 with header line,
 T_VBFS type table of VBFS,
 T_VBLS type table of VBLS.
call function 'GN_DELIVERY_CREATE'
exporting
 VBSK_I = VBSK_I
tables
 XKOMDLGN = T_KOMDLGN[]
 XVBFS = T_VBFS
 XVBLS = T_VBLS.
perform ASSIGN.
*& Form assign
 text
--> p1 text
<-- p2 text
form ASSIGN .
data: NAME_TAB1(30) type C value '(SAPLV50S)XKOMDLGN'.
 KOMDLGN type table of KOMDLGN with header line.
field-symbols: .
if SY-SUBRC = 0.
 KOMDLGN = <KOMDLGN>.
endif.
assign: (NAME_TAB1) to <KOMDLGN>.
if SY-SUBRC = 0.
 KOMDLGN[] = <KOMDLGN>.
endif.
check not KOMDLGN[] is initial.
endform. " assign
If you call Funktion 'GN_DELIVERY_CREATE' then the ASSIGN dumps. If you don't call it, then the ASSIGN gives you a returncode 4. The funktion works within the GN_DELIVERY_CREATE, however, the relevant coding is in the Program SAPMV50A in the performroutine USEREXIT_REFRESH_DOCUMENT. I get the dump when the exit is called by WS_DELIVERY_UPDATE, or RV_DELIVERY_CREATE. These functions don't know the Table XKOMDLGN.
So, if you find a solution to your problem, please let me know. I think I have the same problem.
Greetings,
Maria Frölich.

ASSIGN TO FIELD SYMBOL

Hi,
in user exit EXIT_SAPLVEDA_001.
data: wa_xvbap like line of xvbap.
FIELD-SYMBOLS: <fs_xvbap> like wa_xvbap.
ASSIGN '(SAPLVEDA)XVBAP' TO <fs_xvbap>.
getting error of type incompatible..
any ideas?
Thanks
Giri

Hi,
you are trying to assign a string '(SAPLVEDA)XVBAP' to a field symbol with type XVBAP. You are just missing brackets.
ASSIGN ('(SAPLVEDA)XVBAP') TO <fs_xvbap>.
Cheers

Checking whether field-symbol from another program is assigned?

Hi all
I'm attempting to access a FS from another program.
As the FS can be assigned, or unassigned within that program, how do I checked for that in my calling program?
e.g. calling program;
FIELD-SYMBOLS: <fs> TYPE STANDARD TABLE.
DATA: lv_var(40) type c.
lv_var = '(ZTGT_PROG)<read_fs>'.
ASSIGN (lv_var) TO <fs>. " statement might dump...

Hi
Go through this doc and use accordingly
Field Symbols
Field symbols are placeholders or symbolic names for other fields. They do not physically reserve space for a field, but point to its contents. A field symbol cam point to any data object. The data object to which a field symbol points is assigned to it after it has been declared in the program.
Whenever you address a field symbol in a program, you are addressing the field that is assigned to the field symbol. After successful assignment, there is no difference in ABAP whether you reference the field symbol or the field itself. You must assign a field to each field symbol before you can address the latter in programs.
Field symbols are similar to dereferenced pointers in C (that is, pointers to which the content operator * is applied). However, the only real equivalent of pointers in ABAP, that is, variables that contain a memory address (reference) and that can be used without the contents operator, are reference variables in ABAP Objects.
All operations programmed with field symbols are applied to the field assigned to it. For example, a MOVE statement between two field symbols moves the contents of the field assigned to the first field symbol to the field assigned to the second field symbol. The field symbols themselves point to the same fields after the MOVE statement as they did before.
You can create field symbols either without or with type specifications. If you do not specify a type, the field symbol inherits all of the technical attributes of the field assigned to it. If you do specify a type, the system checks the compatibility of the field symbol and the field you are assigning to it during the ASSIGN statement.
Field symbols provide greater flexibility when you address data objects:
If you want to process sections of fields, you can specify the offset and length of the field dynamically.
You can assign one field symbol to another, which allows you to address parts of fields.
Assignments to field symbols may extend beyond field boundaries. This allows you to address regular sequences of fields in memory efficiently.
You can also force a field symbol to take different technical attributes from those of the field assigned to it.
The flexibility of field symbols provides elegant solutions to certain problems. On the other hand, it does mean that errors can easily occur. Since fields are not assigned to field symbols until runtime, the effectiveness of syntax and security checks is very limited for operations involving field symbols. This can lead to runtime errors or incorrect data assignments.
While runtime errors indicate an obvious problem, incorrect data assignments are dangerous because they can be very difficult to detect. For this reason, you should only use field symbols if you cannot achieve the same result using other ABAP statements.
For example, you may want to process part of a string where the offset and length depend on the contents of the field. You could use field symbols in this case. However, since the MOVE statement also supports variable offset and length specifications, you should use it instead. The MOVE statement (with your own auxiliary variables if required) is much safer than using field symbols, since it cannot address memory beyond the boundary of a field. However, field symbols may improve performance in some cases.
check the below links u will get the answers for your questions
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3860358411d1829f0000e829fbfe/content.htm
http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
http://searchsap.techtarget.com/tip/1,289483,sid21_gci920484,00.html
Syntax Diagram
FIELD-SYMBOLS
Basic form
FIELD-SYMBOLS <fs>.
Extras:
1. ... TYPE type
2. ... TYPE REF TO cif
3. ... TYPE REF TO DATA
4. ... TYPE LINE OF type
5. ... LIKE s
6. ... LIKE LINE OF s
7. ... TYPE tabkind
8. ... STRUCTURE s DEFAULT wa
The syntax check performed in an ABAP Objects context is stricter than in other ABAP areas. See Cannot Use Untyped Field Symbols ad Cannot Use Field Symbols as Components of Classes.
Effect
This statement declares a symbolic field called <fs>. At runtime, you can assign a concrete field to the field symbol using ASSIGN. All operations performed with the field symbol then directly affect the field assigned to it.
You can only use one of the additions.
Example
Output aircraft type from the table SFLIGHT using a field symbol:
FIELD-SYMBOLS <PT> TYPE ANY.
DATA SFLIGHT_WA TYPE SFLIGHT.
ASSIGN SFLIGHT_WA-PLANETYPE TO <PT>.
WRITE <PT>.
Addition 1
... TYPE type
Addition 2
... TYPE REF TO cif
Addition 3
... TYPE REF TO DATA
Addition 4
... TYPE LINE OF type
Addition 5
... LIKE s
Addition 6
... LIKE LINE OF s
Addition 7
... TYPE tabkind
Effect
You can define the type of the field symbol using additions 2 to 7 (just as you can for FORM parameters (compare Defining the Type of Subroutine Parameters). When you use the ASSIGN statement, the system carries out the same type checks as for USING parameters of FORMs.
This addition is not allowed in an ABAP Objects context. See Cannot Use Obsolete Casting for FIELD SYMBOLS.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Defining Types Using STRUCTURE.
Effect
Assigns any (internal) field string or structure to the field symbol from the ABAP Dictionary (s). All fields of the structure can be addressed by name: <fs>-fieldname. The structured field symbol points initially to the work area wa specified after DEFAULT.
The work area wa must be at least as long as the structure s. If s contains fields of the type I or F, wa should have the structure s or at least begin in that way, since otherwise alignment problems may occur.
Example
Address components of the flight bookings table SBOOK using a field symbol:
DATA SBOOK_WA LIKE SBOOK.
FIELD-SYMBOLS <SB> STRUCTURE SBOOK
DEFAULT SBOOK_WA.
WRITE: <SB>-BOOKID, <SB>-FLDATE.
Related
ASSIGN, DATA
Additional help
Declaring Field Symbols
Reward points if useful
Regards
Anji

Problem with slis_t_specialcol_alv Field Symbol Assignment

I have created a dynamic internal table (runtime determined number of columns) to contain data to be displayed in an ALV. Ive also made ensured that the last column of the dynamic itab is of type 'slis_t_specialcol_alv' and named CINFO to contain color information for that particular row. In the code below the dynamic itab is pointed to by field symbol <dyn_table> while the work area for it would be <dyn_wa>.
Somewhere down the line I attempt to assign the CINFO component of the current row of the itab to a field symbol called <fs_cinfo> typed as slist_t_specialcol_alv (Same as CINFO).
I used the code:
ASSIGN COMPONENT 'CINFO' OF STRUCTURE <dyn_wa> TO <fs_cinfo>.
This gives me the runtime error:
Type conflict in the ASSIGN statement in the program "ZHRR001_TEMMATRIX".
You attempted to assign a field to a typed field symbol,
but the field does not have the required type. 
I am unsure why this happens as both the component CINFO and FS <fs_cinfo> are of type slist_t_specialcol_alv.
For some odd reason though during debugging, I took a look at the <dyn_wa> structure and the component type of CINFO was displayed as C???
Here is the relevant portion of code (creation of dynamic itab and attempting to assign <fs_cinfo>)
FIELD-SYMBOLS: <dyn_table> TYPE STANDARD TABLE,
 <dyn_wa>.
FIELD-SYMBOLS: <fs_cinfo> TYPE slist_t_specialcol_alv.
DATA: lw_cinfo TYPE slis_specialcol_alv.
DATA: li_fldcat TYPE lvc_t_fcat,
 lw_fldcat TYPE lvc_s_fcat.
*Create internal table fields (they will be called Field1, Field2, etc)
*Last column will be named 'CINFO' to contain row color information
DO l_alvcolumncount TIMES.
index = sy-index.
IF index <> l_alvcolumncount.
 CLEAR lw_fldcat.
 CONCATENATE 'Field' index INTO lw_fldcat-fieldname .
 CONDENSE lw_fldcat-fieldname NO-GAPS.
 lw_fldcat-datatype = 'STRING'.
* lw_fldcat-intlen = 5.
 APPEND lw_fldcat TO li_fldcat .
ELSE.
 CLEAR lw_fldcat.
 lw_fldcat-fieldname = 'CINFO'.
 CONDENSE lw_fldcat-fieldname NO-GAPS.
 lw_fldcat-datatype = 'slis_t_specialcol_alv'.
 APPEND lw_fldcat TO li_fldcat.
ENDIF.
ENDDO.
* Create dynamic internal table and assign to FS
CALL METHOD cl_alv_table_create=>create_dynamic_table
EXPORTING
 it_fieldcatalog = li_fldcat
IMPORTING
 ep_table = new_table.
ASSIGN new_table->* TO <dyn_table>.
*Create dynamic work area and assign to FS
CREATE DATA new_line LIKE LINE OF <dyn_table>.
ASSIGN new_line->* TO <dyn_wa>.
ASSIGN COMPONENT 'CINFO' OF STRUCTURE <dyn_wa> TO <fs_cinfo>.
* Color this cell
lw_cinfo-fieldname = fieldname.
lw_cinfo-color-col = 6.
APPEND lw_cinfo TO <fs_cinfo>.
Message was edited by: Sow Yong Wong

Hello Sow
There is a big problem in the program: you are mixing types used for FM-based ALV (SLIS_...) and ABAP-OO based ALV (LVC_...).
For ABAP-OO based row colouring you have to define your itab like this:
TYPES: ty_s_outtab.
INCLUDE TYPE kna1. " just an example
TYPES: rowcolor(4) TYPE c.
TYPES: END OF ty_s_outtab.
TYPES: ty_t_outtab TYPE STANDARD TABLE of ty_s_outtab
 WITH DEFAULT KEY.
In the layout (LVC_S_LAYO) you have to set ls_layout-info_fname = 'ROWCOLOR'.
ROWCOLOR has to be filled according to Cxyz whereas
- x = color
- y = inverse on/off
- z = intensified on/off
For documentation please refer to <a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/e8a1d690-0201-0010-b7ad-d9719a415907">An Easy Reference to ALV Grid Control</a>
Regards
Uwe

Assigning field value to Field symbol

Dear Experts,
I have one program which works fine in non unicode system.. The program contains Assign statement with offset and length..
This program dumps in Unicode system due to this instruction.. The field which i want to assign to field symbol is type P field..
Is there any ways to avoid the dump?
Thank you in Advance..

Hi,
isn't it an ABAP question in an EP forum?
Romano

Assigning field symbol to a form parameter

Hello there.
I got this huge string that concatenates several columns from a structure and I have to distribute these data into fields of a generic work area in a FORM.
The thing is that I can't find the right way to pass this work area and when I try to assign my field symbol a dump occurs.
Could anyone give me a tip?
Here is what I'm doing:
Form Nameform <how to pass?> p_workarea
loop at it_tab
 CONCATENATE 'p_table-' it_tab-fieldname INTO campo.
 ASSIGN (campo) TO <fs>.
endloop.
When I debug it, the program sees p_workarea, but when I try to see a specific field like p_workarea-kunnr, it's like it doesn't exists.

Thanks Matt,
But how do I append the values within this internal table ??
When I am using the following code:
ls_wa-fld3 = 'A'.
ls_wa-t_in-fld1 = 'B'.
ls_wa-t_in-fld2 = 'C'.
ls_wa-t_in-fld1 = 'D'.
ls_wa-t_in-fld2 = 'E'.
append ls_wa to lt_tab.
Its giving an error that:
The data object "LS_WA" does not have a component called "T_IN-FLD1".
I wanted the values to be appended in the following way in lt_tab:
fld3 fld1 fld2
A B C
 D E
Please help.

Field name retrieval from field symbols after assigning to field in a struc

We have an internal table of about 100 columns. First 7 of them have key values and other fields are data fields. Out of remaining 93 fields, any 2 to 3 fields have data stored in it in each record. Using field symbols in a loop (93 fixed iterations), we are identifying which fields has a data in it. Once we identify the field, how do we retrieve the name of the field / column of the table. We are performing further processing based on name of the field.
Any ideas how to get the name of the column assigned to field symbols?
sample raw code piece is as below:
clear n.
Do 93 times.
n = n + 1.
assign component n of structure itab to <fs>.
if not <fs> is initial.
Get name of the field in cfname.
perform process_record using cfname.
endif.
enddo.
Thanks.
Regards.

Hi,
Try this..use the function module GET_COMPONENT_LIST to get the fields of the internal table and store it in an internal table ITAB_COMP..
Then use READ TABLE ITAB_COMP INDEX sy-index..
You can get the field name from the work area..
Thanks,
Naren

How to use field symbols in program

how to use field symbols can any one explain with example please..
Regards,
venki...

Hi
Field Symbols
Field symbols are placeholders or symbolic names for other fields. They do not physically reserve space for a field, but point to its contents. A field symbol cam point to any data object. The data object to which a field symbol points is assigned to it after it has been declared in the program.
Whenever you address a field symbol in a program, you are addressing the field that is assigned to the field symbol. After successful assignment, there is no difference in ABAP whether you reference the field symbol or the field itself. You must assign a field to each field symbol before you can address the latter in programs.
Field symbols are similar to dereferenced pointers in C (that is, pointers to which the content operator * is applied). However, the only real equivalent of pointers in ABAP, that is, variables that contain a memory address (reference) and that can be used without the contents operator, are reference variables in ABAP Objects.
All operations programmed with field symbols are applied to the field assigned to it. For example, a MOVE statement between two field symbols moves the contents of the field assigned to the first field symbol to the field assigned to the second field symbol. The field symbols themselves point to the same fields after the MOVE statement as they did before.
You can create field symbols either without or with type specifications. If you do not specify a type, the field symbol inherits all of the technical attributes of the field assigned to it. If you do specify a type, the system checks the compatibility of the field symbol and the field you are assigning to it during the ASSIGN statement.
Field symbols provide greater flexibility when you address data objects:
If you want to process sections of fields, you can specify the offset and length of the field dynamically.
You can assign one field symbol to another, which allows you to address parts of fields.
Assignments to field symbols may extend beyond field boundaries. This allows you to address regular sequences of fields in memory efficiently.
You can also force a field symbol to take different technical attributes from those of the field assigned to it.
The flexibility of field symbols provides elegant solutions to certain problems. On the other hand, it does mean that errors can easily occur. Since fields are not assigned to field symbols until runtime, the effectiveness of syntax and security checks is very limited for operations involving field symbols. This can lead to runtime errors or incorrect data assignments.
While runtime errors indicate an obvious problem, incorrect data assignments are dangerous because they can be very difficult to detect. For this reason, you should only use field symbols if you cannot achieve the same result using other ABAP statements.
For example, you may want to process part of a string where the offset and length depend on the contents of the field. You could use field symbols in this case. However, since the MOVE statement also supports variable offset and length specifications, you should use it instead. The MOVE statement (with your own auxiliary variables if required) is much safer than using field symbols, since it cannot address memory beyond the boundary of a field. However, field symbols may improve performance in some cases.
check the below links u will get the answers for your questions
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3860358411d1829f0000e829fbfe/content.htm
http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
http://searchsap.techtarget.com/tip/1,289483,sid21_gci920484,00.html
Syntax Diagram
FIELD-SYMBOLS
Basic form
FIELD-SYMBOLS <fs>.
Extras:
1. ... TYPE type
2. ... TYPE REF TO cif
3. ... TYPE REF TO DATA
4. ... TYPE LINE OF type
5. ... LIKE s
6. ... LIKE LINE OF s
7. ... TYPE tabkind
8. ... STRUCTURE s DEFAULT wa
The syntax check performed in an ABAP Objects context is stricter than in other ABAP areas. See Cannot Use Untyped Field Symbols ad Cannot Use Field Symbols as Components of Classes.
Effect
This statement declares a symbolic field called <fs>. At runtime, you can assign a concrete field to the field symbol using ASSIGN. All operations performed with the field symbol then directly affect the field assigned to it.
You can only use one of the additions.
Example
Output aircraft type from the table SFLIGHT using a field symbol:
FIELD-SYMBOLS <PT> TYPE ANY.
DATA SFLIGHT_WA TYPE SFLIGHT.
ASSIGN SFLIGHT_WA-PLANETYPE TO <PT>.
WRITE <PT>.
Addition 1
... TYPE type
Addition 2
... TYPE REF TO cif
Addition 3
... TYPE REF TO DATA
Addition 4
... TYPE LINE OF type
Addition 5
... LIKE s
Addition 6
... LIKE LINE OF s
Addition 7
... TYPE tabkind
Effect
You can define the type of the field symbol using additions 2 to 7 (just as you can for FORM parameters (compare Defining the Type of Subroutine Parameters). When you use the ASSIGN statement, the system carries out the same type checks as for USING parameters of FORMs.
This addition is not allowed in an ABAP Objects context. See Cannot Use Obsolete Casting for FIELD SYMBOLS.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Defining Types Using STRUCTURE.
Effect
Assigns any (internal) field string or structure to the field symbol from the ABAP Dictionary (s). All fields of the structure can be addressed by name: <fs>-fieldname. The structured field symbol points initially to the work area wa specified after DEFAULT.
The work area wa must be at least as long as the structure s. If s contains fields of the type I or F, wa should have the structure s or at least begin in that way, since otherwise alignment problems may occur.
Example
Address components of the flight bookings table SBOOK using a field symbol:
DATA SBOOK_WA LIKE SBOOK.
FIELD-SYMBOLS <SB> STRUCTURE SBOOK
DEFAULT SBOOK_WA.
WRITE: <SB>-BOOKID, <SB>-FLDATE.
Reward points for useful Answers
Regards
Anji

Field-Symbols to get field contents from a different program

Hi All,
I have seen code like this in some programs.
 clear: field.
 move '(SAPLIQS0)VIQMEL' to field.
 assign (field) to <fs_qmel>.
Does this mean that the contents of the field VIQMEL in program SAPLIQS0 would be assigned to Field-Symbol <fs_qmel>. Also should the program SAPLIQSO be also running at the same time? Are there any variations of achieving the same?
Thanks again..!
Jr.

When I define my fs as a table, the program abends on the following:
ASSIGN (field) to <fs>.
I only have field defined as follows:
data: field like xvbap.
I have tried a few things to define "field", however with no luck!!!
Thanks for the quick response.
Regards,
Trisha

Problem with DESCRIBE field-symbol statement?

Hi
I havw written following querry but it's showing error. My doubt is there any resctriction field symbols in DESCRIBE query.
i wrote
describe field <a> type typ length in character mode.
Is that syntax correct?

When you use the Describe statement with the field symbols, it will do the describe on the field which was assigned to it.
Like:
FIELD-SYMBOLS: <fs> TYPE ANY.
DATA: l_char TYPE char10.
l_char = 'TEST'.
ASSIGN l_char TO <fs>.
DATA: l_len TYPE i.
DESCRIBE FIELD <fs> LENGTH l_len IN CHARACTER MODE.
write: / '<fs>:', <fs>.
WRITE: / 'Length', l_len.
Here descirbe gives the property of the L_CHAR because it was assigned to field symbol <FS>.
Regards,
Naimesh Patel

The difference between FIELD-SYMBOL and normal DATA TYPE

Dear experts,
Please see the example below, both are output the same result.
DATA: EXTERNAL_RECORD(4000),
 POSITION TYPE I,
 LENGTH TYPE N,
 ENTRY TYPE STRING.
EXTERNAL_RECORD = '0005Smith0007Edwards0005Young'.
DO.
LENGTH = EXTERNAL_RECORD+POSITION(4).
IF LENGTH = 0.
 EXIT.
ENDIF.
ADD 4 TO POSITION.
MOVE EXTERNAL_RECORD+POSITION(LENGTH) TO ENTRY.
WRITE ENTRY.
ADD LENGTH TO POSITION.
IF POSITION >= 4000.
 EXIT.
ENDIF.
ENDDO.
--OR It can be written as--
DATA: EXTERNAL_RECORD(4000),
 POSITION TYPE I,
 LENGTH TYPE N.
FIELD-SYMBOLS <ENTRY>.
EXTERNAL_RECORD = '0005Smith0007Edwards0005Young'.
DO.
LENGTH = EXTERNAL_RECORD+POSITION(4).
IF LENGTH = 0.
 EXIT.
ENDIF.
ADD 4 TO POSITION.
ASSIGN EXTERNAL_RECORD+POSITION(LENGTH) TO <ENTRY>.
WRITE <ENTRY>.
ADD LENGTH TO POSITION.
IF POSITION >= 4000.
 EXIT.
ENDIF.
ENDDO.
Is there any special circumstances we need to use FIELD-SYMBOL?
Why is FIELD-SYMBOL is introduce in the first place?
Kindly advice with example.
Thanks in advance for those who can help me on this.

HI,
You can use field symbols to make the program more dynamic. In this example the name of a table control is substituted by a field symbol. Thus you cal call the form with any internal table, using the name of the table control as a parameter.
Example
form insert_row
using p_tc_name.
field-symbols <tc> type cxtab_control. "Table control
assign (p_tc_name) to <tc>.
insert 100 lines in table control
<tc>-lines = 100.
Field symbols allow you to:
** Assign an alias to a data object(for example, a shortened
 name for data objects structured through several hierarchies
 - <fs>-f instead of rec1-rec2-rec3-f)
** Set the offset and length for a string variably at runtime
** Set a pointer to a data object that you determine at runtime (dynamic ASSIGN)
** Adopt or change the type of a field dynamically at runtime
** Access components of a structure
** (from Release 4.5A) Point to lines of an internal table
 (process internal tables without a separate work area)
Field symbols in ABAP are similar to pointers in other programming
languages. However, pointers (as used in PASCAL or C) differ from ABAP
field symbols in their reference syntax.
The statement ASSIGN f to <fs> assigns the field f to field
symbol <fs>. The field symbol <fs> then "points" to the
contents of field f at runtime. This means that all changes to the
contents of f are visible in <fs> and vice versa. You declare
the field symbol <fs> using the statement FIELD-SYMBOLS: <fs>.
Reference syntax
Programming languages such as PASCAL and C use a dereferencing symbol
to indicate the difference between a reference and the object to which
it refers; so PASCAL would use p^ for a pointer instead of p, C would
use *p instead of p. ABAP does not have any such dereferencing symbol.
** In PASCAL or C, if you assign a pointer p1 to a pointer p2,
you force p1 to point to the object to which p2 refers (reference semantics).
** In ABAP, if you assign a field symbol <fs1> to a field
symbol <fs2>, <fs1> takes the value of the data object to
which <fs2> refers (value semantics).
** Field symbols in ABAP are always dereferenced, that is,
they always access the referenced data object. If you want to
change the reference yourself in ABAP, you can use the ASSIGN statement
to assign field symbol <fs1> to field symbol <fs2>.
Using field symbols
You declare field symbols using the FIELD-SYMBOLS statement.
They may be declared either with or without a specific type.
At runtime you assign a field to the field symbol using the ASSIGN
statement. All of the operations on the field symbol act on the field
assigned to it.
When you assign a field to an untyped field symbol, the field symbol
adopts the type of the field. If, on the other hand, you want to assign
a field to a typed field symbol, the type of the field and that of the
field symbol must be compatible.
A field symbol can point to any data object and from Release 4.5A,
they can also point to lines of internal tables.
The brackets (<>) are part of the syntax.
Use the expression <fs> IS ASSIGNED to find out whether the field
symbol <fs> is assigned to a field.
The statement UNASSIGN <fs> sets the field symbol <fs> so
that it points to nothing. The logical expression <fs>
IS ASSIGNED is then false. The corresponding negative expression
is IF NOT <fs> IS ASSIGNED.
An unassigned field symbol <fs> behaves as a constant with
type C(1) and initial value SPACE.
MOVE <fs>
TO dest Transfers the initial value SPACE to the variable dest
MOVE 'A' to <fs>
Not possible, since <fs> is a constant
(runtime error).
To lift a type restriction, use the CASTING addition in the
ASSIGN statement. The data object is then interpreted as though
it had the data type of the field symbol. You can also do this
with untyped field symbols using the CASTING TYPE <type> addition.
The danger with pointers is that they may point to invalid areas.
This danger is not so acute in ABAP, because the language does not
use address arithmetic (for example, in other languages, pointer p
might point to address 1024. After the statement p = p + 10, it would
point to the address 1034). However, the danger does still exist, and
memory protection violations lead to runtime errors.
A pointer in ABAP may not point beyond a segment boundary. ABAP does
not have one large address space, but rather a set of segments.
Each of the following has its own segment:
* All global data
* All local data
* Each table work area (TABLES)
* Each COMMON PART
You should only let field symbols move within an elementary field or
structure where ABAP allows you to assign both within the global data
and beyond a field boundary.
Rgds
Umakanth

How to use field symbol in select

Hi,
 CONCATENATE 'WTG0' LV_MON INTO LV_FNAME.
 ASSIGN (LV_FNAME) TO <FS>.
 SELECT SINGLE <FS> FROM COSP INTO LV_SAPRST
 WHERE OBJNR = LV_OBJ AND GJAHR = LV_YEAR AND WRTTP = '4' AND KSTAR = GT_INOUT-SAKNR
 Error message : Unknown column name "<FS>" . field list. . field list. field list.
 actually , if i use if command, i can do, but i want to use simple code by fieldsymbol.
 is it possible in select command?
Thanks in advance
Benjamin

Hi
Hope it will help you.
reward if help.
Field Symbols
Field symbols are placeholders or symbolic names for other fields. They do not physically reserve space for a field, but point to its contents. A field symbol cam point to any data object. The data object to which a field symbol points is assigned to it after it has been declared in the program.
Whenever you address a field symbol in a program, you are addressing the field that is assigned to the field symbol. After successful assignment, there is no difference in ABAP whether you reference the field symbol or the field itself. You must assign a field to each field symbol before you can address the latter in programs.
Field symbols are similar to dereferenced pointers in C (that is, pointers to which the content operator * is applied). However, the only real equivalent of pointers in ABAP, that is, variables that contain a memory address (reference) and that can be used without the contents operator, are reference variables in ABAP Objects.
All operations programmed with field symbols are applied to the field assigned to it. For example, a MOVE statement between two field symbols moves the contents of the field assigned to the first field symbol to the field assigned to the second field symbol. The field symbols themselves point to the same fields after the MOVE statement as they did before.
You can create field symbols either without or with type specifications. If you do not specify a type, the field symbol inherits all of the technical attributes of the field assigned to it. If you do specify a type, the system checks the compatibility of the field symbol and the field you are assigning to it during the ASSIGN statement.
Field symbols provide greater flexibility when you address data objects:
If you want to process sections of fields, you can specify the offset and length of the field dynamically.
You can assign one field symbol to another, which allows you to address parts of fields.
Assignments to field symbols may extend beyond field boundaries. This allows you to address regular sequences of fields in memory efficiently.
You can also force a field symbol to take different technical attributes from those of the field assigned to it.
The flexibility of field symbols provides elegant solutions to certain problems. On the other hand, it does mean that errors can easily occur. Since fields are not assigned to field symbols until runtime, the effectiveness of syntax and security checks is very limited for operations involving field symbols. This can lead to runtime errors or incorrect data assignments.
While runtime errors indicate an obvious problem, incorrect data assignments are dangerous because they can be very difficult to detect. For this reason, you should only use field symbols if you cannot achieve the same result using other ABAP statements.
For example, you may want to process part of a string where the offset and length depend on the contents of the field. You could use field symbols in this case. However, since the MOVE statement also supports variable offset and length specifications, you should use it instead. The MOVE statement (with your own auxiliary variables if required) is much safer than using field symbols, since it cannot address memory beyond the boundary of a field. However, field symbols may improve performance in some cases.
check the below links u will get the answers for your questions
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3860358411d1829f0000e829fbfe/content.htm
http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
http://searchsap.techtarget.com/tip/1,289483,sid21_gci920484,00.html
Syntax Diagram
FIELD-SYMBOLS
Basic form
FIELD-SYMBOLS <fs>.
Extras:
1. ... TYPE type
2. ... TYPE REF TO cif
3. ... TYPE REF TO DATA
4. ... TYPE LINE OF type
5. ... LIKE s
6. ... LIKE LINE OF s
7. ... TYPE tabkind
8. ... STRUCTURE s DEFAULT wa
The syntax check performed in an ABAP Objects context is stricter than in other ABAP areas. See Cannot Use Untyped Field Symbols ad Cannot Use Field Symbols as Components of Classes.
Effect
This statement declares a symbolic field called <fs>. At runtime, you can assign a concrete field to the field symbol using ASSIGN. All operations performed with the field symbol then directly affect the field assigned to it.
You can only use one of the additions.
Example
Output aircraft type from the table SFLIGHT using a field symbol:
FIELD-SYMBOLS <PT> TYPE ANY.
DATA SFLIGHT_WA TYPE SFLIGHT.
ASSIGN SFLIGHT_WA-PLANETYPE TO <PT>.
WRITE <PT>.
Addition 1
... TYPE type
Addition 2
... TYPE REF TO cif
Addition 3
... TYPE REF TO DATA
Addition 4
... TYPE LINE OF type
Addition 5
... LIKE s
Addition 6
... LIKE LINE OF s
Addition 7
... TYPE tabkind
Effect
You can define the type of the field symbol using additions 2 to 7 (just as you can for FORM parameters (compare Defining the Type of Subroutine Parameters). When you use the ASSIGN statement, the system carries out the same type checks as for USING parameters of FORMs.
This addition is not allowed in an ABAP Objects context. See Cannot Use Obsolete Casting for FIELD SYMBOLS.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Defining Types Using STRUCTURE.
Effect
Assigns any (internal) field string or structure to the field symbol from the ABAP Dictionary (s). All fields of the structure can be addressed by name: <fs>-fieldname. The structured field symbol points initially to the work area wa specified after DEFAULT.
The work area wa must be at least as long as the structure s. If s contains fields of the type I or F, wa should have the structure s or at least begin in that way, since otherwise alignment problems may occur.
Example
Address components of the flight bookings table SBOOK using a field symbol:
DATA SBOOK_WA LIKE SBOOK.
FIELD-SYMBOLS <SB> STRUCTURE SBOOK
DEFAULT SBOOK_WA.
WRITE: <SB>-BOOKID, <SB>-FLDATE.
Related
ASSIGN, DATA
Additional help
Declaring Field Symbols

Assign statement - Assign program field to field symbol

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