topic Re: lock objects in Application Development and Automation Discussions

lock objects

Former Member — Wed, 16 May 2007 06:15:16 GMT

Hi,

Any one please tell me why we use lock object while deleting the table entries

Regards,

Venkat

Re: lock objects

Former Member — Wed, 16 May 2007 06:17:24 GMT

so that if someone else is trying to do some modifications with the same entry in the table, he will not allowed to do so because of lock objects.

Regards,

Atish

Re: lock objects

Former Member — Wed, 16 May 2007 06:18:30 GMT

Hi,

pls go through

Hi,

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.

pls reward if it helpful

Thanks

Vana

Re: lock objects

Former Member — Wed, 16 May 2007 06:19:28 GMT

Hi,

Lock objects are used to lock the database table while making the modifications on the database table.

you can create your own lock objects using SE11.

if you create lock objects on any table system will create two function modules.

1.ENQUEUE....

2.DEQUEUE.....

first one is used to lock the table

second one used to removing lock on the table.

*----

lock Table

CALL FUNCTION 'ENQUEUE_E_TABLE'

EXPORTING

tabname = table_name

EXCEPTIONS

foreign_lock = 1

system_failure = 2

OTHERS = 3.

*----

Unlock Table

CALL FUNCTION 'DEQUEUE_E_TABLE'

EXPORTING

tabname = table_name

check this link :

http://help.sap.com/saphelp_40b/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm

_SCOPE = 1: The lock is not sent to the update program. The lock is removed when the transaction is ended.

_SCOPE = 2: The lock is sent to the update program. The update program is responsible for removing the lock. The dialog program which requested the lock no longer has an influence on the lock behavior. This is the standard setting for the ENQUEUE function module.

_SCOPE = 3: The lock is also sent to the update program. The lock must be removed in both the dialog program and by the update program. This is the standard setting for the ENQUEUE function module.

Regards

Reshma

Re: lock objects

former_member196299 — Wed, 16 May 2007 06:25:07 GMT

hi Venkat ,

In simple words , we use lock objects for locking a particular object specially during making any modification on the same, so that its not modified by two sessions at a time . All other informations about lock objects are posted in your thread .

Regards,

Ranjita

Re: lock objects

Former Member — Wed, 16 May 2007 06:27:49 GMT

Hi,

goto tcode abapdocu and select

ABAP Database Access ->SAP Transaction Concept ->Setting and Releasing Locks .

and goto se11 and display the lock object EDEMOFLHT definition.

rgds,

bharat.