topic Re: Locking a custom table in Application Development and Automation Discussions

Locking a custom table

Former Member — Fri, 25 Jan 2008 10:03:48 GMT

Hi All !!

I want to update one custom table which has key fields K1, K2 and K3.

I am using ENQUEUE_E_TABLE to lock the table.But I dont know how to send the table for enqueue.

Nextly, I need to send keys of table .Should I use any structure where I append the key fields and export the structure. The function call is as :

CALL FUNCTION 'ENQUEUE_E_TABLE'

EXPORTING

MODE_RSTABLE = 'E'

TABNAME = ?

VARKEY =?

EXCEPTIONS

FOREIGN_LOCK = 1

SYSTEM_FAILURE = 2

OTHERS = 3

Please help in this regard..

Thanks in advance..

Prabhas.

Re: Locking a custom table

Former Member — Fri, 25 Jan 2008 10:09:16 GMT

Hai.

Check this.

Lock objects are use in SAP to avoid the inconsistancy at the time of data is being insert/change into database.

SAP Provide three type of Lock objects.

- Read Lock(Shared Locked)

protects read access to an object. The read lock allows other transactions read access but not write access to

the locked area of the table

- Write Lock(exclusive lock)

protects write access to an object. The write lock allows other transactions neither read nor write access to

the locked area of the table.

- Enhanced write lock (exclusive lock without cumulating)

works like a write lock except that the enhanced write lock also protects from further accesses from the

same transaction.

You can create a lock on a object of SAP thorugh transaction SE11 and enter any meaningful name start with EZ Example EZTEST_LOCK.

Use: you can see in almost all transaction when you are open an object in Change mode SAP could not allow to any other user to open the same object in change mode.

Example: in HR when we are enter a personal number in master data maintainance screen SAP can't allow to any other user to use same personal number for changes.

Technicaly:

When you create a lock object System automatically creat two function module.

1. ENQUEUE_<Lockobject name>. to insert the object in a queue.

2. DEQUEUE_<Lockobject name>. To remove the object is being queued through above FM.

You have to use these function module in your program.

check this link for example.

http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

tables:vbak.

call function 'ENQUEUE_EZLOCK3'

exporting

mode_vbak = 'E'

mandt = sy-mandt

vbeln = vbak-vbeln

X_VBELN = ' '
_SCOPE = '2'
_WAIT = ' '
_COLLECT = ' '
EXCEPTIONS
FOREIGN_LOCK = 1
SYSTEM_FAILURE = 2
OTHERS = 3

if sy-subrc <> 0.

MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.

endif.

Normally ABAPers will create the Lock objects, because we know when to lock and how to lock and where to lock the Object then after completing our updations we unlock the Objects in the Tables

http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

purpose: If multiple user try to access a database object, inconsistency may occer. To avoid that inconsistency and to let multiple user give the accessibility of the database objects the locking mechanism is used.

Steps: first we create a loc object in se11 . Suppose for a table mara. It will create two functional module.:

1. enque_lockobject

1. deque_lockobject

before updating any table first we lock the table by calling enque_lockobject fm and then after updating we release the lock by deque_lockobject.

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

GO TO SE11

Select the radio button "Lock object"..

Give the name starts with EZ or EY..

Example: EYTEST

Press Create button..

Give the short description..

Example: Lock object for table ZTABLE..

In the tables tab..Give the table name..

Example: ZTABLE

Save and generate..

Your lock object is now created..You can see the LOCK MODULES..

In the menu ..GOTO -> LOCK MODULES..There you can see the ENQUEUE and DEQUEUE function

Lock objects:

http://www.sap-img.com/abap/type-and-uses-of-lock-objects-in-sap.htm

http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

Match Code Objects:

http://help.sap.com/saphelp_nw2004s/helpdata/en/41/f6b237fec48c67e10000009b38f8cf/content.htm

http://searchsap.techtarget.com/tip/0,289483,sid21_gci553386,00.html

See this link:

http://www.sap-img.com/abap/type-and-uses-of-lock-objects-in-sap.htm

Check these links -

Regards.

Sowjanya.B.

Re: Locking a custom table

Former Member — Fri, 25 Jan 2008 10:09:54 GMT

Hi,

CALL FUNCTION 'ENQUEUE_E_TABLE'

EXPORTING

mode_rstable = 'E'

tabname = p_table

VARKEY =
X_TABNAME = ' '
X_VARKEY = ' '
_SCOPE = '2'
_WAIT = ' '
_COLLECT = ' '

EXCEPTIONS

foreign_lock = 1

system_failure = 2

OTHERS = 3 .

Give the table name, the VARKEY is optional.

Thanks,

Sunil

Re: Locking a custom table

former_member404244 — Fri, 25 Jan 2008 10:10:42 GMT

Hi,

Try like this

constants: lc_tabname TYPE rstable-tabname VALUE <give the custom table name>

CALL FUNCTION 'ENQUEUE_E_TABLE'

EXPORTING

MODE_RSTABLE = 'E'

tabname = lc_tabname

EXCEPTIONS

foreign_lock = 1

system_failure = 2

OTHERS = 3.

Regards,

nagaraj

Re: Locking a custom table

Former Member — Fri, 25 Jan 2008 10:23:21 GMT

use the following function module as specified below.

concatenate mandt, K1, K2 , k3 into wf_varkey.

CALL FUNCTION 'ENQUEUE_E_TABLEE'

EXPORTING

MODE_RSTABLE = 'E'

tabname = wf_tabname

varkey = wf_varkey

EXCEPTIONS

foreign_lock = 1

system_failure = 2

OTHERS = 3.

regards,

Gopi,

reward points if helpfull.

Re: Locking a custom table

Former Member — Fri, 25 Jan 2008 10:30:24 GMT

Hello Prabhas,

Here is the program which i used to lock on unlock the database table.

You can see the locking and unloking coding in Bold Letters.

I created this program to delete few records from MARA table. For this program i used this Concept.

REPORT y16v_update_zvleknvv1.

TABLES: mara.

SELECT-OPTIONS: s_matnr FOR mara-matnr.

START-OF-SELECTION.

Lock the table

PERFORM lock.

Deleting the records from the Table

DELETE FROM mara WHERE matnr IN s_matnr.

IF sy-subrc EQ 0.

WRITE 'Deleted'.

ENDIF.

Unlock the table

PERFORM unlock.

**&----

*& Form LOCK

**&----

Lock the Database Table*

**----

FORM lock.

CALL FUNCTION 'ENQUEUE_E_TABLEE'

EXPORTING

mode_rstable = 'E'

tabname = 'MARA'

EXCEPTIONS

foreign_lock = 1

system_failure = 2

OTHERS = 3.

IF sy-subrc 0.

MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno

WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.

ENDIF.

ENDFORM. " LOCK

**&----

*& Form UNLOCK

**&----

Unlock the Database Table*

**----

FORM unlock.

CALL FUNCTION 'DEQUEUE_E_TABLEE'

EXPORTING

mode_rstable = 'E'

tabname = 'MARA'.

ENDFORM. " UNLOCK

Reward If Helpful.

Regards

Sasidhar Reddy Matli.

Re: Locking a custom table

Former Member — Fri, 25 Jan 2008 10:44:23 GMT

Thanks all..great help!!!