Best table lock suggested ??

Question

hi,
i have a scenario as follows:
i am developing a custom transaction, dialog based, basically to perform add/modify/delete data from custom tables. Multiple users can login and try to work on the data, one can add records to the same table and another can modify teh records of the same table. So whats the best kind of table lock to be used ? and how to hande that ?
thks

Answer 1

Hi,
For Locking look at the below code
  DATA: l_v_locktab   TYPE tabname,
        l_v_funcname  TYPE rs38l_fnam,
        l_v_noobj     TYPE flag,
        l_v_garg      TYPE eqegraarg,
        l_i_enq       TYPE STANDARD TABLE OF seqg3.
  IF rb_upd = space.
    EXIT.
  ENDIF.
  l_v_locktab = fp_table.
  CASE l_v_locktab.
    WHEN 'LIPS'.
      l_v_locktab = 'LIKP'.
    WHEN 'VBAP'.
      l_v_locktab = 'VBAK'.
    WHEN 'VBRP'.
      l_v_locktab = 'VBRK'.
    WHEN 'PLPO'.
      l_v_locktab = 'PLKO'.
  ENDCASE.
* Search Lock objects for the table
  SELECT viewname FROM dd25l INTO v_lockobj
         UP TO 1 ROWS
         WHERE aggtype = 'E'
         AND   roottab = l_v_locktab.
  ENDSELECT.
  IF sy-subrc = 0.
    CONCATENATE 'ENQUEUE_' v_lockobj INTO l_v_funcname.
*   Check if the  Enqueue function is OK
    SELECT SINGLE funcname FROM tfdir INTO l_v_funcname
                  WHERE funcname = l_v_funcname.
    IF sy-subrc = 0.
      CALL FUNCTION l_v_funcname
*       EXPORTING
*         MANDT                = SY-MANDT
*         _SCOPE               = '2'
*         _WAIT                = ' '
*         _COLLECT             = ' '
       EXCEPTIONS
         foreign_lock         = 1
         system_failure       = 2
         OTHERS               = 3
      IF sy-subrc <> 0.
        MESSAGE ID sy-msgid TYPE 'I' NUMBER sy-msgno
                WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
        LEAVE LIST-PROCESSING.
      ENDIF.
    ELSE.
      CLEAR v_lockobj.
      l_v_noobj = 'X'.
    ENDIF.
  ELSE.
    CLEAR v_lockobj.
    l_v_noobj = 'X'.
  ENDIF.
*   If No lock object is found for the table, do a general check.
*   Read Locks
  IF l_v_noobj = 'X'.
    CALL FUNCTION 'ENQUEUE_READ'
     EXPORTING
        gname                       = fp_table
*       GARG                        = ' '
        guname                      = space
*       LOCAL                       = ' '
*     IMPORTING
*       NUMBER                      =
*       SUBRC                       =
      TABLES
        enq                         = l_i_enq
     EXCEPTIONS
       communication_failure       = 1
       system_failure              = 2
       OTHERS                      = 3
    IF l_i_enq[] IS NOT INITIAL.
      MESSAGE i023.
      LEAVE LIST-PROCESSING.
    ELSE.
      CONCATENATE fp_table '*' INTO l_v_garg.
      CALL FUNCTION 'ENQUEUE_READ'
       EXPORTING
          gname                       = 'RSTABLE'
          garg                        = l_v_garg
          guname                      = space
*         LOCAL                       = ' '
*       IMPORTING
*         NUMBER                      =
*         SUBRC                       =
        TABLES
          enq                         = l_i_enq
       EXCEPTIONS
         communication_failure       = 1
         system_failure              = 2
         OTHERS                      = 3.
      IF l_i_enq[] IS NOT INITIAL.
        MESSAGE i023.
        LEAVE LIST-PROCESSING.
      ENDIF.
    ENDIF.
* if No Lock exists. Do a common lock
    CALL FUNCTION 'ENQUEUE_E_TABLE'
     EXPORTING
*      MODE_RSTABLE         = 'E'
       tabname              = fp_table
*      VARKEY               =
*      X_TABNAME            = ' '
*      X_VARKEY             = ' '
*      _SCOPE               = '2'
*      _WAIT                = ' '
*      _COLLECT             = ' '
     EXCEPTIONS
       foreign_lock         = 1
       system_failure       = 2
       OTHERS               = 3
    IF sy-subrc <> 0.
      MESSAGE ID sy-msgid TYPE 'I' NUMBER sy-msgno
              WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
      LEAVE LIST-PROCESSING.
    ENDIF.
  ENDIF.
for unlocking
  DATA: l_v_funcname  TYPE rs38l_fnam.
  IF v_lockobj NE space.
*   if Lock Object is available
    CONCATENATE 'DEQUEUE_' v_lockobj INTO l_v_funcname.
*   Check if the  Dequeue function is OK
    SELECT SINGLE funcname FROM tfdir INTO l_v_funcname
                  WHERE funcname = l_v_funcname.
    IF sy-subrc = 0.
      CALL FUNCTION l_v_funcname.
    ENDIF.
  ELSE.
*  Do a common Unlock
    CALL FUNCTION 'DEQUEUE_E_TABLE'
     EXPORTING
*     MODE_RSTABLE       = 'E'
      tabname            = fp_table
*     VARKEY             =
*     X_TABNAME          = ' '
*     X_VARKEY           = ' '
*     _SCOPE             = '3'
*     _SYNCHRON          = ' '
*     _COLLECT           = ' '
  ENDIF.
Shreekant