06-21-2007 8:48 AM
HI,
WHAT IS Lock Object AND HOW TO CREAT Lock Object.
THANK YOU
ASHOK KUMAR
06-21-2007 8:51 AM
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.
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.
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.
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.
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 -
<b>Reward points for useful Answers</b>
Regards
Anji
06-21-2007 8:51 AM
Hi Ashok
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.
Hope this will give a basic idea.
check these links
http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm
http://help.sap.com/saphelp_nw04/helpdata/en/7b/f9813712f7434be10000009b38f8cf/content.htm
http://articles.techrepublic.com.com/5100-6329_11-5066352.html
Reward all helpfull answers
Regards
Pavan
Message was edited by:
Pavan praveen
06-21-2007 8:52 AM
Ashok,
Lock Objects are used to synchronize access to the same data by
more than one user. Function modules that can be used in
application programs are generated from the definition of a lock
object in the ABAP Dictionary.
The R/3 System synchronizes simultaneous access of
several users to the same data records with a lock
mechanism. When interactive transactions are programmed,
locks are set and released by calling function modules .
These function modules are automatically generated from the
definition of lock objects in the ABAP Dictionary.
Structure of a Lock Object
The tables in which data records should be locked with a
lock request are defined in a lock object together with their
key fields.
When tables are selected, one table (the primary table) is
first selected. Further tables (secondary tables) can also be
added using foreign key relationships.
Lock Arguments
The lock argument of a table in the lock object consists of the
key fields of the table.
The lock argument fields of a lock object are used as input
parameters in the function modules for setting and removing
locks generated from the lock object definition. When these
function modules are called, the table rows to be locked or
unlocked are specified by defining certain values in these fields.
These values can also be generic. The lock argument fields
therefore define which subset of the table rows should be
locked.
Data Dictionary/ Lock Objects
The simplest case of a lock object consists of exactly one
table and the lock argument of the table is the primary key of
this table. Several tables can also be included in a lock
object. A lock request therefore can lock an entire logical
object, and not only a record of a table. Such a logical object
can be for example a document comprising an entry in a
header table and N entries in a positiontable.
Lock Mode
The lock mode controls whether several users can access
data records at the same time. The lock mode can be
assigned separately for each table in the lock object. When
the lock is set, the corresponding lock entry is stored in the
lock table of the system for each table.
Access by more than one user can be synchronized in the
following ways:
Exclusive lock: The locked data can only be displayed or
edited by a single user. A request for another exclusive lock
or for a
shared lock is rejected.
Shared lock: More than one user can access the locked data
at the same time in display mode. A request for another
shared lock is
accepted, even if it comes from another user. An exclusive lock
is
rejected.
Exclusive but not cumulative: Exclusive locks can be requested
several times from the same transaction and are processed
successively. In contrast, exclusive but not cumulative locks
can be called only once from the same transaction. All other
lock requests are rejected.
1> Select object type Lock object in the initial screen of the ABAP
Dictionary, enter an object name and choose Create.
The name of a lock object should begin with an E (Enqueue).
The maintenance screen for lock objects is displayed.
2> Enter an explanatory short text in the field Short text.
You can then use the short text to find the lock object at a later
time, for example with the R/3 Repository Information System.
3> Enter the name of the primary table of the lock object.
All other tables in the lock object must be linked with the
primary table using foreign keys.
4> Select the lock mode of the primary table in the field below
it.
The lock mode is used as the default value for the
corresponding parameters of the function modules generated
from the lock object.
5> Choose Add if you want to lock records in more than one
table with the lock object.
A list of all the tables linked with the primary table using valid
foreign keys is displayed. Select the appropriate table. The lock
mode of the primary table is copied as lock mode. You can
change this setting as required, for example you can assign the
lock mode separately for each table.
Similarly, you can add a table linked with the secondary table
just added with foreign keys. To do this, place the cursor on
the name of the secondary table and choose Add.
If no lock mode is assigned to a table, no lock is set for the
entries in this table when the generated function modules are
called. You should not assign a lock mode if a secondary table
was only used to define a path between the primary table and
another secondary table with foreign keys.
6> Save your entries.
A dialog box appears in which you have to assign the lock
object a development class.
7> You can define whether the function modules generated from
the lock object should be RFC-enabled on the Attributes tab
page. If you set the Allow RFC flag, the generated function
modules can be called from within another system with Remote
Function Call. If you permit Remote Function Calls for an
existing lock object, you must ensure that the generated
function modules are called from within an ABAP program with
parameters appropriate for the type. You should therefore check
all programs that use the associated function modules before
activating the lock object with the new option.
8> Choose Activate.
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
Don't forget to reward if useful..
06-21-2007 9:00 AM
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.
Hope this will give a basic idea.
<b>Creating the Lock Objects</b> http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eef3446011d189700000e8322d00/content.htm
Regards
Sudheer