What is control tables in abap hr?what is the purpose?

Question

what is control tables in abap hr?what is the purpose?

Answer 1

These are the screen elements used to display tabular data they can be called
as screen tables( like STEP LOOP).To use table control we have to create it on the screen using SCREEN PAINTER(SE51) and declare a control variable of TYPE TABLEVIEW using CONTROLS statement in the ABAP program. We have to use LOOP .. ENDLOOP statement in both PBO and PAI with or without AT int_table parameter. IF AT int_table parameter is not used than we have to place a MODULE call between the LOOP...ENDLOOP statement to fill the screen table rows from the ABAP program in PBO and program our own scrolling functions
using OK_CODE field.
Having a parallel loop(at screen table rows & int table rows) by using parameter
AT int_table makes the ABAP code simple.
A special structure of type CXTAB_CONTROL is used to set/get various
attributes of table control at runtime like CURRENT_LINE ,TOP_LINE.
ABAP declaration
CONTROLS: tab_con TYPE TABLEVIEW USING SCREEN nnnn
Here tab_con is the same name we used in screen for the table control.
This ABAP statement will declare a control variable that will be used to access
the table control , and set it's various attributes like number of fixed columns(tab_con-FIXED_COLS) ,total number of records it will display(tab_con-LINES).It is of type CXTAB_CONTROL and is a deep structure(structure containing structures).
REFRESH CONTROL tab_con FROM SCREEN nnnn
This ABAP statement will initialize the table control on the screen nnnn to its initial values.
PBO processingI
n PBO we have to use the screen LOOP ...ENDLOOP statement , with or without
intenal table.
LOOP WITH CONTROL tab_con.
MODULE fill_tab_con.
ENDLOOP.
Here a module should be called between the loop endloop statement to transfer
data from th ABAP program to the screen table through a structure.This module
should use the CURRENT_LINE attribute of the table control variable to get the
current screen table record index to read the data from the internal table into a work area.
e.g.
READ TABLE int_table INDEX tab_con-CURRENT_LINE
The record read will be placed in the header line of the internal table and will be available to the similarly named screen fields or if these are different it can be written explicitly. e.g.
screen_field_name = int_table-field_name
LOOP AT int_table INTO workarea WITH CONTROL tab_con CURSOR i FROM
n1 TO n2.
ENDLOOP.
Here the module call is not required to fill the screen table.The CURSOR parameter is a integer of type I indicating which absolute internal table line
should be the first to display on the table control .FROM n1 TO n2 can be used
to restrict the starting line and ending line number of the internal table , they are of type SY-TABIX.
In both cases before the LOOP statement a module should be called which
is generally for setting of status ,in which we should fill the LINES attribute
(tab_con-LINES ) of the control with the total number of internal table records,doing this ensures correct and automatic scrolling.
The ABAP statement DESCRIBE TABLE int_table LINES lines can be used
to get the total lines in an int table.
PAI Processing
We have to use LOOP ... ENDLOOP in PAI so that data can transfer fro table control to ABAP program. If we want to write changes to the data we should
call a module between the LOOP ... ENDLOOP. The MODULE call to process user commands (SY-UCOM) should be called after the ENDLOOP statement.
e.g.
PROCESS AFTER INPUT
MODULE mod AT EXIT-COMMAND.
LOOP AT itab_table or LOOP "depending on whether we are using AT int_table
MODULE modify_int_table.
ENDLOOP.
MODULE user_command.
In the MODULE call modify_int_table we can use
MODIFY int_table FROM workarea INDEX tab_con-CURRENT_LINE
or we can use
int_table-field_name = screen_field_name.
Thanks
Please Reward points if helpful.
Edited by: Richa Khosla on Mar 28, 2008 7:38 AM