Steps to create table control

The values specified for the size category and data class are mapped to database-specific values via control tables.

1. Declare the table control

As well as drawing the table control on the screen it is necessary to declare the table control as a data item (in the TOP include program for the transaction).

CONTROLS ctrl TYPE TABLEVIEW USING SCREEN scr. is the name of the table control on a screen in the ABAP program
corresponds to a complex type – (CXTAB_CONTROL defined in the ABAP dictionary) is the screen from which the table control will get its initial values

2. Adding table control to a screen

In the graphical screen editor choose the table control element button. Use the left mouse button to position and size the control on the screen.

Then input the name of the table control.

3. Adding field to table control

To add a field to table control, we can retrieve from table or internal table. Click on the icon dictionary/program field window or function key F6.

There two option while retrieve field, i.e. based on database table or internal table. If want to retrieve from database table, input the name of table then click push button “Get from Dictionary”.If want to retrieve from internal table, input the internal table name then click push button “Get from program”.’

Read more about SAP R3 systems

Mark the field to be added to table control, and then click on the push button OK.

Drag selected fields into a table then release the mouse button.

Here the fields we selected will be displayed in reversed order. I do not exactly why it happens. I have tried some ways and tricks to display in the correct order, but the fields are still displayed in reversed order. Finally, to get the correct order I selected the fields one by one.

4. Adding a label for each column

The label column is a text field. To add it, just click on the text field icon, drag it onto the header of the column, and then type the label.

Table Control Principle

There are a set of programming principles that should be adhered to when using table controls and step loops.

Data from the database should be initially loaded into an internal table. This means the database is accessed for reading purposes only once in the transaction.

Next, the rows of the internal table are loaded into the table control. Any changes made to the data are then saved back to the internal table. At the end of the transaction, the contents of the internal table can be written back to the database, again to minimize database I/O.

PAI logic for screen 1 (see screen below) loads the internal table with data from the database according to the entries supplied by the user.
PBO logic for screen 2 (see screen below) populates the table control from the internal table (buffer).
User action in screen 2 triggers the PAI logic. PAI logic updates the internal table with new values entered (into the table control screen fields) by the user.
PAI logic is triggered by actions such as scrolling down a single row as well as actions such as BACK, EXIT, etc.
Unless the user action causes the transaction to leave the current screen, after the PAI modules have been executed, the PBO modules for the screen are executed again. Thus the table control fields are updated or refreshed after every user action.

PBO (Process Before Output)

In PBO processing fields are transported from the module pool to the screen in a predefined order.

The table control step loop is processed row by row. Fields with corresponding names are transported from the module pool to the screen.
After the step loop has been processed all remaining module pool fields are transported to the screen.

PAI (Process After Input)

All screen fields that do not belong to a table control and are not specified in a FIELD statement are transported to module pool fields
Table control fields are transported row by row to module pool fields
Fields specified in FIELD statements are transported immediately before the FIELD statement is executed

Updating data in table control

The ABAP language provides two mechanisms for loading the table control with data from the internal table and then storing the altered rows of the table control back to the internal table.

1) Method 1: Read the internal table into the Table Control in the screen’s flow logic. Used when the names of the Table Control fields are based on internal table fields.

2) Method 2: Read the internal table into the Table Control in the module pool code. Used when the names of the Table Control fields are based on fields of the
database table.

Method 1 (table control fields = itab fields)

We can read an internal table using the LOOP statement in the flow logic. Define the reference to the relevant able control by specifying WITH CONTROL

Determine which table entry is to be read by specifying CURSOR -CURRENT_LINE.

After the read operation, the field contents are placed in the header line of the internal table. If the fields in the table control have the same name as the internal they will be filled automatically. Otherwise, we need to write a module to transfer the internal table fields to the screen fields.

We must reflect any changes the user makes to the fields of the table control in the internal table otherwise they will not appear when the screen is redisplayed after PBO processing, (eg, after the user presses Enter or scrolls) However, this processing should be performed only if changes have actually been made to the screen fields of the table control (hence the use of the ON REQUEST)

PROCESS BEFORE OUTPUT.
LOOP AT ITAB_REG WITH CONTROL TCREG
CURSOR TCREG-CURRENT_LINE.
ENDLOOP.
PROCESS AFTER INPUT.
LOOP AT ITAB_REG.
MODULE MODIFY_ITAB_REG.
ENDLOOP.
MODULE MODIFY_ITAB_REG INPUT.
MODIFY ITAB_REG INDEX TCREG-CURRENT_LINE.
ENDMODULE.
Method 2 (table control fields = dict. fields)

If using an LOOP statement without an internal table in the flow logic, we must read the data in a PBO module which is called each time the loop is processed.

Since the system cannot determine the number of internal table entries itself, we must use the EXIT FROM STEP-LOOP statement to ensure that no blank lines are displayed in the table control if there are no more corresponding entries in the internal table.

PROCESS BEFORE OUTPUT.
LOOP WITH CONTROL TCREG.
MODULE READ_ITAB_REG.
ENDLOOP.
PROCESS AFTER INPUT.
LOOP WITH CONTROL TCREG.
CHAIN.
FIELD: ITAB_REG-REG,
ITAB_REG-DESC.
MODULE MODIFY_ITAB_REG
ON CHAIN-REQUEST.
ENDCHAIN.
ENDLOOP.
MODULE READ_ITAB_REG OUTPUT.
READ TABLE ITAB_REG INDEX TCREG-CURRENT_LINE.
I IF SY-SUBRC EQ 0.
MOVE-CORRESPONDING ITAB_REREG TO TCREG.
ELSE.
EXIT FROM STEP-LOOP.
ENDIF.
ENDMODULE.
MODULE MODIFY_ITAB_REG INPUT.
MOVE-CORRESPONDING TCREG TO ITAB_REG.
MODIFY ITAB_REG INDEX
TCREG-CURRENT_LINE.
ENDMODULE.
Updating the internal table

Method 1

PROCESS AFTER INPUT.
LOOP AT ITAB_REG.
CHAIN.
FIELD: ITAB_REG-REG,
ITAB_REG-DESC.
MODULE MODIFY_ITAB_REG ON CHAIN-REQUEST.
ENDCHAIN.
ENDLOOP.
MODULE MODIFY_ITAB_REG INPUT.
ITAB_REG-MARK = 'X'.
MODIFY ITAB_REG INDEX TCREG-CURRENT_LINE.
ENDMODULE.

Method 2

PROCESS AFTER INPUT.
LOOP WITH CONTROL TCREG.
CHAIN.
FIELD: TCREG-REG,
TCREG-DESC.
MODULE MODIFY_ITAB_REG ON CHAIN-REQUEST.
ENDCHAIN.
ENDLOOP.
MODULE MODIFY_ITAB_REG INPUT.
MOVE-CORRESPONDING TCREG TO ITAB_REG.
I TAB_REG-MARK = 'X'.
MODIFY ITAB_REG INDEX TCREG-CURRENT_LINE.
ENDMODULE.

Updating the database

MODULE USER_COMMAND_100.
CASE OK_CODE.
WHEN ‘SAVE’.
LOOP AT ITAB-REG.
CHECK ITAB_REG-MARK = ‘X’.
MOVE-CORRESPONDING ITAB_REG TO TCREG.
UPDATE TCREG.
ENDLOOP.
WHEN ...
...
ENDCASE.
ENDMODULE.

Those are the simple steps how to create table control.

Create Table Control