topic Re: LUW in Application Development and Automation Discussions

LUW

Former Member — Fri, 21 Mar 2008 17:23:34 GMT

hi experts,

can u please explain me following questions

1.what is LUW ?

2. what is SAP LUW.?

3.Every data base is providing by default DB LUW then why SAP is providing SAP LUW?

4.what are lock objects?

5.if SAP is providing by default lock objects why we have to use?.when we have to use?

please provide explanations for above questions?

Thanks & Regards,

Re: LUW

Former Member — Fri, 21 Mar 2008 17:28:40 GMT

1.what is LUW ?

Logical Unit of Work

2. what is SAP LUW.?

Generally this relates to DB activity and is equal to the time between COMMITs

3.Every data base is providing by default DB LUW then why SAP is providing SAP LUW?

4.what are lock objects?

If I'm understanding yoru question correctly, Lock objects are issued by your program to prevent another user from attempting to

update the same record while you have it open for update.

5.if SAP is providing by default lock objects why we have to use?.when we have to use?

See answer to 4.

Re: LUW

Former Member — Fri, 21 Mar 2008 17:52:01 GMT

1.what is LUW ?

Logical ounit of work

2. what is SAP LUW.?

sap provided luw

3.Every data base is providing by default DB LUW then why SAP is providing SAP LUW?

See luw is provided by all the erp's but here comes the main difference between the other erp's and sap .

when u r using 5 different servers to upload data when one system gets updated with the data but unfortunately due to some technical problems if the other systems are unable to update the data then the mismatching of data problem arises.

so to avoid this luw comes into act and removes the updated data from first server where the data is updated.

4.what are lock objects?

Lock objects are nothing but u can see create them using se11 u can see the last radio button

the main usage is if 100 persons want to access the same data base will face problem

to avoid this lock objects are introduced...

using this 2 functional modules of lock objects enque and deque u can lock and modify then delock that one

5.if SAP is providing by default lock objects why we have to use?.when we have to use?

if u understand 4th answer u can asnwer 5 by ur self if not reply me ok bye

sas

Reward points if usefull

Edited by: saslove sap on Mar 21, 2008 6:52 PM

Re: LUW

Former Member — Sat, 22 Mar 2008 06:02:46 GMT

Hi paul and sas,

thank u for ur reply.but till now i did n't get clear explanation.

please provide me detial description

Thanks & Regards,

Re: LUW

Former Member — Sat, 22 Mar 2008 07:11:43 GMT

Hi Gopi,

2. what is SAP LUW?

An SAP LUW is a logical unit consisting of dialog steps, whose changes are written to the database in a single database LUW. There are various bundling techniques that you can use to ensure that all of the database updates belonging to an SAP LUW are made in the same single database LUW.

3. Every data base is providing by default DB LUW then why SAP is providing SAP LUW?

SAP LUW are database independent and can work accross different kinds of DB's that are available in the market.

The Open SQL statements INSERT, UPDATE, MODIFY, and DELETE allow you to program database changes with the help of SAP LUW.

4. What are lock objects?

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 (see Function Modules for Lock Requests). These function modules are automatically generated from the definition of lock objects in the ABAP Dictionary.

Re: LUW

Former Member — Sat, 22 Mar 2008 07:32:32 GMT

Hi Gopi,

LUW: Indivisible business process, which is performed either completely or not at all.

Related sequence of programming units which when executed can be distributed across several work processes (several database LUWs) as with, for example, dialog steps or remote function calls. However, database changes are made within one single database LUW. SAP LUWs are carried out by grouping techniques in which update function modules or subroutines, among other things, are registered in various work processes and executed by one single work process. An SAP LUW is completed by the open SQL statement COMMIT WORK. Changes within an SAP LUW can be undone with the open SQL statement ROLLBACK WORK.

An SAP LUW usually has the same function as a dialog transaction (which maps a business process) and maps database changes made in dialog transactions to an update. A dialog transaction can, however, also include several SAP LUWs.

Lock bjects Are Used to Synchronys Access to same data by more than One user.

Suppose You that u have opened the Program and if any one is trying to access the same by another user then it will show the same program in Display Mode. so SAP will Automaticaly take care of the Things About Locking.

Suppose U Have Created A Transaction Code. Suppose U If u want Give Authorization Some User Only Than u have to Use Lock Objects.

Please go through this link for further info:

https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/8bde9690-0201-0010-ed8e-8787eae24388#q-2

Hope it solves your concern...:)

Regards,

Eshwar.

Re: LUW

Former Member — Sat, 22 Mar 2008 08:29:12 GMT

Hi,

LUW is the unit of work either completed fully(committed) or not completed even a bit (Rollback).

If different users are working on the same data and one gui is deleting the data and another gui is modifying the data. Then the second person will face a problem which is already is deleted. To overcome such situations SAP has provided a locking mechanism. We have to create lock objects in SE11. The system automatically create two functions enque and deque functions which are used in the programs to lock and unlock particular record of the database table.

The SAP canot allow two users working on the change mode.

reward.

Re: LUW

Former Member — Sat, 22 Mar 2008 08:38:32 GMT

Hi,

Please refer below links :

For LUW:

http://help.sap.com/saphelp_47x200/helpdata/en/41/7af4c2a79e11d1950f0000e82de14a/frameset.htm

For Lock Objects

http://help.sap.com/saphelp_47x200/helpdata/en/cf/21eea5446011d189700000e8322d00/frameset.htm

Thanks,

Sriram Ponna.