commitchange function not work properly

Hi All, I have some difficulties when I am doing update operation on database table.

DB table looks like

ID   Component1   Component1_Desc   Component2   Component2_Desc  Component3  Component3_Desc
1    _                  NULL                                        NULL                                        NULL
2                        NULL                                        NULL                                        NULL

Value of column 'Component1', 'Component2', 'Component3' for second record is '  ' (Space).

In my table layout setting, I selected Component1, Component2, Component3. (Component Type: Text Field )

I believe that I setup virture form properly because I can save updates on first record.

However, any changes I made on second records disappear after I call commitchange()
I suspect there is sth to do with the ' ' in column1, column2 and column3.

There is no error message displayed.

Please help me. Thanks in advance.



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public String btnSave_action() {
       
        try{
           
            prb_myprb_trackingDataProvider.commitChanges();
            prb_myprb_trackingDataProvider.refresh();
        }catch(Exception ex){
            log("Error Description", ex);
            error(ex.getMessage());
        }
       
        return null;
    }