Header Line Logic for Field Symbols??
Hi Experts,
I have the logic
DATA: Itab TYPE REF TO DATA.
FIELD-SYMBOLS: <itab> TYPE STANDARD TABLE.
CREATE DATA Itab TYPE STANDARD TABLE OF (TABLE_NAME).
ASSIGN Itab->* TO <itab>.
Her I had done the dynamic logic
select (LT_FIELDS)
into corresponding fields of table <itab>
from (TABLE_NAME)
up to 100 rows
WHERE (LT_WHERE).
Now I am having all information in <itab>.
Now I want to take this headerline information of <itab> and populate the same to other structure??
How to take the <itab> as header line information by looping??
Hi
see this and use
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.
Regards
ANJI
Similar Messages
-
DATA_OFFSET_TOO_LARGE dump for field symbol assignment/offset
Hi,
I am getting a DATA_OFFSET_TOO_LARGE dump for field symbol assignment/offset.
Dump says, 'In the running program "ZTEST", the field "<WA_FINAL>" of the type "u" and length 2174 was to be accessed with the offset 2204. However, subfield accesses with an offset specification that is not smaller than the field length are not permitted.'
Here <WA_FINAL> have to be 'TYPE any' to avoid assignment conflicts later in the logic.
It's basically dumping at <WA_FINAL>+V_LEN(V_OFF) = WA_DATA-FIELD1.
Here V_LEN LIKE DD03L-LENG & V_OFF LIKE DD03L-LENG.
Please suggest how to get rid of this dump.
Regards,
Ritesh.The dump is very clear, your field is smaller than the offset.
The problem is most likely how you are calculating v_len and v_off.
You could change that, but there is probably an easier and faster way to do what you are trying there. Is <wa_final> something like a line from a file or what? -
Sample program for field symbol
hi,
I am fresher. I want sample program(code) for field symbol.http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
TYPES: BEGIN OF line,
col1 TYPE c,
col2 TYPE c,
END OF line.
DATA: wa TYPE line,
itab TYPE HASHED TABLE OF line WITH UNIQUE KEY col1,
key(4) TYPE c VALUE 'COL1'.
FIELD-SYMBOLS <fs> TYPE ANY TABLE.
ASSIGN itab TO <fs>.
READ TABLE <fs> WITH TABLE KEY (key) = 'X' INTO wa.
The internal table ITAB is assigned to the generic field symbol <FS>, after which it is possible to address the table key of the field symbol dynamically. However, the static address
READ TABLE <fs> WITH TABLE KEY col1 = 'X' INTO wa.
is not possible syntactically, since the field symbol does not adopt the key of table ITAB until runtime. In the program, the type specification ANY TABLE only indicates that <FS> is a table. If the type had been ANY (or no type had been specified at all), even the specific internal table statement READ TABLE <FS> would not have been possible.
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb387a358411d1829f0000e829fbfe/content.htm
http://help.sap.com/saphelp_nw2004s/helpdata/en/fc/eb387a358411d1829f0000e829fbfe/content.htm -
Better alternative to header lines, use of logical database, field-symbols
Hello experts,
I am wondering if theres a better and faster alternative than declaring a header line for an itab. are work areas faster?
What is the use of logical database? can you please give me an example on how to use it in reports.
how do I use field-symbols? I am confused on how it works.
P.S. I recently installed SAP netweaver preview abap edition
in my home PC and I am wondering if I could practice BDC, user exits, etc. If so, how?
Again, thanks for all your help since I'm kinda new to ABAP.I always use this...It uses header lines, but at least is smaller -:)
<b>DATA: BEGIN OF MY_TAB TYPE STANDARD TABLE OF BKPF WITH HEADER LINE.</b>
For logical databases, you can check my blog...I always use LDB for HR programs -:)
<a href="/people/alvaro.tejadagalindo/blog/2006/02/19/how-to-deal-with-hr-payroll-reports:///people/alvaro.tejadagalindo/blog/2006/02/19/how-to-deal-with-hr-payroll-reports
LDB's provides a lot of information, because they gather it from a lot of different tables...
A Field-Symbols is like a pointer in C++, like an alias for a variable...Here's a small example...
REPORT Z_ATG_DUMMY.
FIELD-SYMBOLS: <F1>, <F2> TYPE I.
DATA: TEXT(20) TYPE C VALUE 'Hello, how are you?',
NUM TYPE I VALUE 5,
BEGIN OF LINE1,
COL1 TYPE F VALUE '1.1e+10',
COL2 TYPE I VALUE '1234',
END OF LINE1,
LINE2 LIKE LINE1.
ASSIGN TEXT TO <F1>.
ASSIGN NUM TO <F2>.
DESCRIBE FIELD <F1> LENGTH <F2>.
TEXT = 'CHAU'.
WRITE: / <F1>, 'has length', NUM.
WRITE: / TEXT, 'has length', NUM.
ASSIGN LINE1 TO <F1>.
ASSIGN LINE2-COL2 TO <F2>.
MOVE <F1> TO LINE2.
ASSIGN 'LINE2-COL2 =' TO <F1>.
I just can't install SAPNWSP...I only got MiniSap...But I got all the development enviorment...Don't know about the User-Exits...Actually I don't think so...Because those "mini" systems doesn't come with any functional module.
Greetings,
Blag. -
Hi All,
I want to apply field symbol technique in my report. actually i have one internal table say i_itab.
it contains fileds like address1 address2 address3 address4 upto address5 . insted of writting each field i want to use field symbol which will increment the counter for field durine runtime. actually i want ot apply this logic for one of my finance report for calculation of periods values hsl01 to hsl16.
can any one give me the solution for how to do this?
thanks in advance
vinod p.Hello Vinod,
If you are trying like this:
CONCATENATE 'wa_remittance_dt-suppl_addr_line' l_cnt2 into l_v_field. " --> Incorrect
ASSIGN l_v_field to <l_v_fields>. " --> Incorrect
You are not assigning the memory area of wa_remittance_dt-suppl_addr_line1 to <l_v_fields>. You are assigning the memory area of l_v_field to <l_v_fields>. Because of this you are getting the blank value.
But if you try like this:
CONCATENATE 'suppl_addr_line' l_cnt2 into l_v_field. "Add this line
ASSIGN COMPONENT l_v_field OF STRUCTURE wa_remittance_dt TO <l_v_fields>.
You are assigning memory area of wa_remittance_dt-suppl_addr_line1 to <l_v_fields>. And after
<l_v_fields> = wa_i_address-l_addr
the value in wa_remittance_dt-suppl_addr_line1 will be changed to that in wa_i_address-l_addr.
I think this should be clear to you.
BR,
Suhas -
Append a new line while using Field Symbols
Hi,
Below is a snippet of my code
DATA: ls_data_package LIKE LINE OF DATA_PACKAGE[].
FIELD-SYMBOLS:<ls_data_package> LIKE LINE OF DATA_PACKAGE[].
zbib_sysn_temp = <ls_data_package>-/bic/zbib_sysn+off3(off4).
<ls_data_package>-/bic/zd_user = <ls_data_package>-/bic/zbib_sysn(off).
<ls_data_package>-/bic/zwrk = <ls_data_package>-/bic/zbib_sysn+off1.
I want to insert a new line to the data package, with all the fields same while adding the above two,
except for,
<ls_data_package>-/bic/zd_user = zbib_sysn_temp
<ls_data_package>-/bic/zitm = 2.
Note: by default the field /bic/zitm = 1. So while adding for the 1st time it is set to 1 by default. I want to add a second (new line) to the datapackage which has all fields same except for the /bic/zd_user and the /bic/zitm = 2.
Please help me with this code,
CDSouvrav, thanks for the reply.
I am not an ABAP'er, I have managed to write code so far. Can you please help me with how this can be done in this code:
DATA: off, off1, off2, off3, off4, off5, off6 TYPE i.
DATA: zbib_sysn_temp TYPE string.
DATA: ls_data_package LIKE LINE OF DATA_PACKAGE[].
FIELD-SYMBOLS:<ls_data_package> LIKE LINE OF DATA_PACKAGE[].
SORT DATA_PACKAGE BY /bic/zbib_id.
LOOP AT DATA_PACKAGE ASSIGNING <ls_data_package>.
IF <ls_data_package>-/bic/zbib_sysn IS NOT INITIAL.
TRANSLATE <ls_data_package>-/bic/zbib_sysn TO UPPER CASE.
FIND '/' IN <ls_data_package>-/bic/zbib_sysn MATCH OFFSET off2.
zbib_sysn_temp = <ls_data_package>-/bic/zbib_sysn+off3(off4).
IF sy-subrc EQ 0.
<ls_data_package>-/bic/zd_user =
<ls_data_package>-/bic/zbib_sysn(off).
Now at this point of code i want to copy this existing record from ls_data_package to create a new record where /bic/zd_user = zbib_sysn_temp and /bic/zitm = 2.
Pleas help... -
Delete Reference for field symbol
Hi
i have thes code
FUNCTION Z_DEMO.
*"*"Local Interface:
*" IMPORTING
*" REFERENCE(INCLUDE_STRUCTURE) TYPE TABNAM
*" TABLES
*" DATA_PACKAGE_TA
DATA: it_data TYPE REF TO data.
FIELD-SYMBOLS: <fs_itab> TYPE STANDARD TABLE.
CREATE DATA it_data TYPE STANDARD TABLE OF (INCLUDE_STRUCTURE).
ASSIGN it_data->* TO <fs_itab>.
assign DATA_PACKAGE_TA[] to <fs_it_dp>.
sort <fs_itab> by ('COSTCENTER') ('CALMONTH') ('CURRENCY').
delete adjacent duplicates
from <fs_itab>
comparing ('COSTCENTER') ('CALMONTH') ('CURRENCY').
(1) Its workes good but it delete lines from DATA_PACKAGE_TA also how i can delete just from
the field symbol <fs_itab> and keep the itab without change ????
(2) How I can build an another itab like DATA_PACKAGE_TA ??????
Thanks and regardes .hi!
instead of:
assign DATA_PACKAGE_TA[] to <fs_itab>.
just do like this:
<fs_itab>[] = DATA_PACKAGE_TA[].
then you can delete from <fs_itab> without deleting the other internal table.
Bye,
Andrew83.
Hope this help you. -
Problem in color a cell for field symbol table.
Hi guru's
when i'm trying to color a cell based on condition, getting the following error.
ERROR: the data object <line> has no structure and therefore no component called "cell_colour" .
providing my code here:
DATA: wa_cellcolor TYPE lvc_s_scol,
lv_index TYPE sy-tabix.
break satishkumarc.
LOOP AT <table> ASSIGNING <line>.
lv_index = sy-tabix.
ASSIGN COMPONENT 'COMPLIANCE' OF STRUCTURE <line> TO <field>.
IF <field> EQ 'YES'.
wa_cellcolor-fname = 'COMPLIANCE'.
wa_cellcolor-color-col = col_positive.
wa_cellcolor-color-int = 0.
wa_cellcolor-color-inv = 0.
ELSE.
wa_cellcolor-fname = 'COMPLIANCE'.
wa_cellcolor-color-col = col_negative.
wa_cellcolor-color-int = 0.
wa_cellcolor-color-inv = 0.
ENDIF.
APPEND wa_cellcolor TO <line>-cell_colour. " error line
MODIFY <table> FROM <line> INDEX lv_index TRANSPORTING cell_colour. " error line
CLEAR: wa_cellcolor.
ENDLOOP.
actually i know that <line>-cell_colour won't work. but i don't know how to achive this functionality .
could anybody please help me out in this.
Thanks in Advance.
regards
satish
thankhi ashish,
i'm using
field-symbols: <line> type any.
CREATE DATA mydata LIKE LINE OF <table>.
ASSIGN mydata->* TO <line>.
to make the structure. so i guess i cannot give the structure name while declaring <line>.
Thanks & regards
satish -
Header line missing for multiple records in the Receiver Email.
I have a file to email scenario
I see the content in mapping has proper output with all the HDRs and ITMS. but when it comes throught the receiver it is missing the HDRs.
Source
HDR1*** ITM1*** ITM2****
HDR2*** ITM1*** ITM2***ITM3**
The email Body looks like the following:
HDR1*** ITM1*** ITM2***ITM1** ITM2***ITM3*
I am missing the HDR for the subsequent recodrs and the subsequent items are shown as if they are the items of the first HDR1. I checked the Mapping the mapping output and it looks good, but when i actually get the email i see it missing susequent HDRs.When I was at a client on 11.5.10, I ended up creating a personalization on the Requisitions screen.
If someone created a requisition with 2 ship to orgs, it raised an error.
It was not full proof but it was deemed satisfactory by the client.
You can consider personalization or you can modify the requisition approval workflow to include the check for multiple ship-to condition.
Hope this helps
Sandeep Gandhi
Independent Techno-functional Consultant -
Hi,
my problem is the following:
DATA: actual_data TYPE TABLE OF actual_tab.
DATA: plan_data TYPE TABLE OF plan_tab.
IF p_act = 'X'.
ASSIGN actual_data TO <p_return_tab>.
ELSEIF p_plan = 'X'.
ASSIGN plan_data TO <p_return_tab>.
ENDIF.
now unfortunately
describe table <p_return_tab> lines n.
does not work, as i do not have an internal table.
how can I find out, how many lines there are?
thanks!
MargitHI,
i am getting the values here
DATA: itab type table of mara .
data lines type i.
field-symbols: <ab> like itab.
start-of-selection.
SELECT * frOM mara INTO TABLE itab UP TO 2 ROWS.
assign itab to <ab>.
describe table <ab> lines lines.
write:/ lines.
Regards,
Venkatesh -
With header line & with out header line ?
what is difference between with header line & without header line ?
When you create an internal table object you can also declare a header line with the same name. You can use the header line as a work area when you process the internal table. The ABAP statements that you use with internal tables have short forms that you can use if your internal table has a header line. These statements automatically assume the header line as an implicit work area. The following table shows the statements that you must use for internal tables without a header line, and the equivalent statements that you can use for internal tables with a header line:
Operations without header line
Operations with header line
Operations for all Table Types
INSERT <wa> INTO TABLE <itab>.
INSERT TABLE ITAB.
COLLECT <wa> INTO <itab>.
COLLECT <itab>.
READ TABLE <itab> ... INTO <wa>.
READ TABLE <itab> ...
MODIFY TABLE <itab> FROM <wa> ...
MODIFY TABLE <itab> ...
MODIFY <itab> FROM <wa> ...WHERE ...
MODIFY <itab> ... WHERE ...
DELETE TABLE <itab> FROM <wa>.
DELETE TABLE <itab>.
LOOP AT ITAB INTO <wa> ...
LOOP AT ITAB ...
Operations for Index Tables
APPEND <wa> TO <itab>.
APPEND <itab>.
INSERT <wa> INTO <itab> ...
INSERT <itab> ...
MODIFY <itab> FROM <wa> ...
MODIFY <itab> ...
Using the header line as a work area means that you can use shorter statements; however, they are not necessarily easier to understand, since you cannot immediately recognize the origin and target of the assignment. Furthermore, the fact that the table and its header line have the same name can cause confusion in operations with entire internal tables. To avoid confusion, you should use internal tables with differently-named work areas.
The following example shows two programs with the same function. One uses a header line, the other does not.
With header line:
TYPES: BEGIN OF LINE,
COL1 TYPE I,
COL2 TYPE I,
END OF LINE.
DATA ITAB TYPE HASHED TABLE OF LINE WITH UNIQUE KEY COL1
WITH HEADER LINE.
DO 4 TIMES.
ITAB-COL1 = SY-INDEX.
ITAB-COL2 = SY-INDEX ** 2.
INSERT TABLE ITAB.
ENDDO.
ITAB-COL1 = 2.
READ TABLE ITAB FROM ITAB.
ITAB-COL2 = 100.
MODIFY TABLE ITAB.
ITAB-COL1 = 4.
DELETE TABLE ITAB.
LOOP AT ITAB.
WRITE: / ITAB-COL1, ITAB-COL2.
ENDLOOP.
Without header line:
TYPES: BEGIN OF LINE,
COL1 TYPE I,
COL2 TYPE I,
END OF LINE.
DATA: ITAB TYPE HASHED TABLE OF LINE WITH UNIQUE KEY COL1,
WA LIKE LINE OF ITAB.
DO 4 TIMES.
WA-COL1 = SY-INDEX.
WA-COL2 = SY-INDEX ** 2.
INSERT WA INTO TABLE ITAB.
ENDDO.
WA-COL1 = 2.
READ TABLE ITAB FROM WA INTO WA.
WA-COL2 = 100.
MODIFY TABLE ITAB FROM WA.
WA-COL1 = 4.
DELETE TABLE ITAB FROM WA.
LOOP AT ITAB INTO WA.
WRITE: / WA-COL1, WA-COL2.
ENDLOOP.
The list, in both cases, appears as follows:
1 1
2 100
3 9
The statements in the program that does not use a header line are easier to understand. As a further measure, you could have a further work area just to specify the key of the internal table, but to which no other values from the table are assigned.
Internal table with header line
you can use anywhere except obkect oriented concept.
Internal table without header line :
You should use in Object oriented concept..
Always try to use without header line,performance point of view it is best..
Example :
Without header line.
Structure
types : begin of ty_itab ,
matnr type mara-matnr,
end of ty_itab.
Internal table
data i_itab type standard table of ty_itab .
Work area
data wa_itab like line of i_itab
With header line
data : begin of i_itab occurs 0,
matnr like mara-matnr,
end of i_itab
itab with header lines are obsolete, anyway it will work but not recommended. instead use work area or more effiecient is field symbols. so donot use itab with header line.
i will explain use of itab w/o header line.
Data: itab1 type standard table of mara with header line occurs 0,
itab2 type standard table of mara,
wa_itab2 type mara.
loop at itab1.
"This will work fine.
endloop.
loop at itab2.
"This will give erro that itabd does not hav workarea
endloop.
"so write
loop at itab2 into wa_itab2.
"This will work
endloop.
<b>The difference between
whih header line and with out heater line of internal table.
ex:-
a) Data : itab like mara occurs 0 with header line.
b) Data: itab like mara occurs 0.
-While adding or retrieving records to / from internal table we have to keep the record temporarily.
-The area where this record is kept is called as work area for the internal table.
-The area must have the same structure as that of internal table. An internal table consists of a body and an optional header line.
-Header line is a implicit work area for the internal table. It depends on how the internal table is declared that the itab will have the header line or not.
a) Data : itab like mara occurs 0 with header line.
table is with header line
b) Data: itab like mara occurs 0.
table is without header line</b>
regards,
srinivas
<b>*reward for useful answers*</b> -
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 -
Field Symbols, Field String, and Field Group.
Hi,
Can you differentiate between filed symbols, field strings and field groups,
With regards,
Bharath Mohan BHi,
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
FIELD GROUPS
are used to hold/handle large amount of data when the internal table are not useful
we use EXTRACT statement, HEADER structure in them
see the example
REPORT demo_extract.
NODES: spfli, sflight.
FIELD-GROUPS: header, flight_info, flight_date.
START-OF-SELECTION.
INSERT: spfli-carrid spfli-connid sflight-fldate
INTO header,
spfli-cityfrom spfli-cityto
INTO flight_info.
GET spfli.
EXTRACT flight_info.
GET sflight.
EXTRACT flight_date.
END-OF-SELECTION.
SORT STABLE.
LOOP.
AT FIRST.
WRITE / 'Flight list'.
ULINE.
ENDAT.
AT flight_info WITH flight_date.
WRITE: / spfli-carrid , spfli-connid, sflight-fldate,
spfli-cityfrom, spfli-cityto.
ENDAT.
AT flight_date.
WRITE: / spfli-carrid , spfli-connid, sflight-fldate.
ENDAT.
AT LAST.
ULINE.
WRITE: cnt(spfli-carrid), 'Airlines'.
ULINE.
ENDAT.
ENDLOOP.
FIELD STRING is nothing but a string with one row of records.
Reward points if useful
regards
Anji -
Multiple Header Line In HIERSEQ ALV
Hi Experts,
Please guide me how to get miltile Header lines in the HIERSEQ Alv , My requirment it develop a genledger for customers in which the Address of customer should be in 3 or four lines then followed by its balances. Please suggest me ...
Regards,
PrakashHi,
You need to pass the Row number to the filed catlog in order to display multiple header lines.
For example,
wl_fieldcat-row_pos = 1. " This field will be displayed in first row
wl_fieldcat-col_pos = 1.
wl_fieldcat-fieldname = 'VBELN'.
wl_fieldcat-tabname = 'T_VBAK'.
wl_fieldcat-outputlen = 20.
Append wl_fieldcat to t_fieldcat.
wl_fieldcat-row_pos = 2. " This field will be displayed in Second row
wl_fieldcat-col_pos = 1.
wl_fieldcat-fieldname = 'VBELN'.
wl_fieldcat-tabname = 'T_VBAK'.
wl_fieldcat-outputlen = 20.
Append wl_fieldcat to t_fieldcat.
Regards,
Rajneesh -
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
BenjaminHi
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
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