SAP LUW and DB LUW

[Former Member]

Hi all

please help me in this regard.my question is "sap luw runs in db luw or db luw runs in sap luw.the previous answers i checked in the forum r a bit confusing bcos in siemens material it says something different.

Thanks and Regards

popin

[raja_thangamani]

A logical unit consisting of dialog steps, whose changes are written to the database in a single database LUW is called an SAP LUW. Unlike a database LUW, an SAP LUW can span several dialog steps, and be executed using a series of different work processes. If an SAP LUW contains database changes, you should either write all of them or none at all to the database. To ensure that this happens, you must include a database commit when your transaction has ended successfully, and a database rollback in case the program detects an error. However, since database changes from a database LUW cannot be reversed in a subsequent database LUW, you must make all of the database changes for the SAP LUW in a single database LUW. To maintain data integrity, you must bundle all of you database changes in the final database LUW of the SAP LUW.

<b>Database LUW vs. SAP LUW</b>

In the case of the database, an LUW is a sequence of data operations that cannot be divided up. The operations are either carried out in full or not at all. Database LUWs are modules that make up the database procedures for consistent data processing.

By way of contrast, an LUW for the SAP System is a business process, which cannot be divided up. The process is either executed in full or not at all. An SAP LUW usually must include several database LUWs (see graphic above), each of which can be terminated with a database COMMIT, which is generated automatically. Under normal circumstances, the SAP LUW contains a dialog part (which maps a business process), and the command for writing the data to the database (update part).

In each database LUW, data is written to the database to special update tables (and not to the application tables). Once the dialog part has been completed, all of the data in a database LUW is transferred into the application tables: the update request is then performed.

Have a look at below link.

http://help.sap.com/saphelp_nw04/helpdata/en/41/7af4bfa79e11d1950f0000e82de14a/content.htm

Raja T

<i>*Please mark all the helpful answers</i>

[Former Member]

Hi popin,

<b>To answer your query simply, SAP LUW contains many DB LUWs</b>.

One DB LUW exists only during the course of a single work process or between two events (commit and/or rollback). We can collect more than one DB LUW into an SAP LUW through Update function modules.

Hope this helps.

Regards,

Aditya

[Former Member]

Hi Popin,

LUW are two types.

1.SAP LUW----COMMIT AT THE END OF TRANSACTION

2.DB LUW------COMMIT AFTER EVERY SCREEN

Database LUW and SAP LUW

In the case of the database, an LUW is a sequence of data operations that cannot be divided up . The operations are either carried out in full or not at all. Database LUWs are modules which go to make up the database procedures for consistent data processing. An R/3 transaction can include several database LUWs (see example above), each of which can be terminated with a database COMMIT, which is generated automatically.

By way of contrast, an LUW for the R/3 System is a business process, which cannot be divided up. The process is either executed in full or not at all. The SAP LUW of an R/3 transaction usually has to contain several database LUWs. Under normal circumstances, it contains a dialog transaction (which maps a business process), and the command for writing the data to the database (update).

In each database LUW, data is written to the database to special update tables (and not to the application tables). Once the dialog area has been completed, all of the data in a database LUW is copied to the application tables: the update request is then performed

http://help.sap.com/saphelp_erp2005vp/helpdata/en/41/7af4c2a79e11d1950f0000e82de14a/frameset.htm

http://help.sap.com/saphelp_erp2005vp/helpdata/en/41/7af4bca79e11d1950f0000e82de14a/frameset.htm

http://help.sap.com/saphelp_erp2005vp/helpdata/en/41/7af4b9a79e11d1950f0000e82de14a/frameset.htm

Pls mark if helpful.

Regards,

Priyanka.