Reg- Data Dictionary

[Former Member]

Hi,

I have created a lock object and view in data dictionary and how can i access these in my abap code.

Kindly expecting replies.

[gopi_narendra]

Hi Satish,

if your lock object name is EZ_LOBJ.

Then you can use the Function modules

ENQUEUE_EZ_LOBJ - to lock

DEQUEUE_EZ_LOBJ - to unlock.

These are the fms generated when creating the Lock Object.

Regards

Gopi

[Former Member]

<b>enque_lockobject</b> is the function module used to apply the lock object.. that is lock the particular object.

<b>dequeue_lockobject</b> will unlock it..

Eg Your lockobject name is ZMSEG

Call the Function module ENQUEUE_ZMSEG in programs, to activate the lock.

check the below link for detail information.

http://help.sap.com/saphelp_nw04/helpdata/en/af/22ab01dd0b11d1952000a0c929b3c3/content.htm

Regards,

Maha

[Former Member]

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_. 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 -

views

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21ecab446011d189700000e8322d00/content.htm

Join, Projection and Selection 

CROSS PRODUCT

Given two tables TABA and TABB. Table TABA has 2 entries and table TABB has 4 entries

Each record of TABA is first combined with each record of TABB. If a join condition is not defined, the cross product of tables TABA and TABB is displayed with the view.

Join condition

A join condition describes how the records of the two tables are connected.

Inner Join and Outer Join 

The data that can be selected with a view depends primarily on whether the view implements an inner join or an outer join.

With an inner join, you only get the records of the cross-product for which there is an entry in all tables used in the view.

With an outer join, records are also selected for which there is no entry in some of the tables used in the view. (ABAP allows left outer join.)

The data that can be selected with a view depends primarily on whether the view implements an inner join or an outer join.

Projection

Sometimes some of the fields of the tables involved in a view are not of interest. The set of fields used in the view can be defined explicitly (projection). In our example, Field 4 is of no interest and can be hidden.

We specify the fields which we need to show in our view by including them under the view flds tab when creating a view in the dictionary.

Selection Conditions

Selection conditions that are used as a filter can be defined for a view.

Specifying these conditions under the Selection conditions tab when creating a view in the dictionary would have an effect which is similar to specifying a where clause when writing a select query to restrict data.