About Logical Database

Hi gurus,
How to restrict the retrieving of data using logical database? I mean, i have a requirement of retrieving Open transaction data only for my program. i used CHECK keyword as well as IF statement but it doesnt work...can anyone tells me those commands that i could use for logical database?? then pls give me some idea also for summation of data (Quantity)
thanks,
nips

Hi,
You simply add the check in the relevant GET event of the LDB.
For example, you may have an event for DOCUMENT as follows.
GET DOCUMENT.
check document-ref in s_ref.
S_REF being your new select option.
a®

Similar Messages

Problem about logical database programming

Dear all,
I have a logical database PRPS_R which contail PRPS and some additional fields.
In my abap report, I call this logical database by "GET PRPS_R". Can I ask how to perform sorting to the logical database in ABAP report?
Thanks
Sunny

PRPS_R is a structure of logical database PSJ
there is a user-exit available EXIT_FDBPS000_001

Idea about Logical DataBase

Hi,
Can, programming with LDB, be considered as an object programming.. just VB, which is an object programming language.
That is we r creating an Object directly and using when ever we want. It is different from OOP where we create a class and instantiate the class to create an object.
My next question is:
There are 2 transactions which we will create, which are basically same except for a text field.
First transaction is posting. And the second one is a reverse posting. In the second transaction we have the reason for reverse posting.
I think in this case we can use LDB and it is the typical scenario where we can apply LDB concept.
Please evaluate me.
-Naveen.

Hi NaveenKumar,
 Logical databases are special ABAP programs that retrieve data and make it available to application programs. The most common use of logical databases is to read data from database tables by linking them to executable ABAP programs.
 However, from Release 4.5A, it has also been possible to call logical databases using the function module LDB_PROCESS. This allows you to call several logical databases from any ABAP program, nested in any way. It is also possible to call a logical database more than once in a program, if it has been programmed to allow this.
 Logical databases contain Open SQL statements that read data from the database. You do not therefore need to use SQL in your own programs. The logical database reads the program, stores them in the program if necessary, and then passes them line by line to the application program or the function module LDB_PROCESS using an interface work area.
Tasks of Logical Databases
1.Reading the same data for several programs.
2.Defining the same user interface for several programs.
3.Central authorization checks
4.Improving performance
First part of your question

 So,if i am not wrong, LDB cannot be completely considered as object oriented programmming.
 I have highlighted some important points above
For understanding this in detail you can go through the sap help .(if you donot know go through the below path
sap library
+ Basis Components
 -Abap Programing and runtime enviornment
 -BC-ABAP Programming(noe serach for ldb
Now your second part of question.
 In the scenario which you have mentioned we can use ldb.But i am not sure whether it is a typical scenario of ldb.LDB is just a specific access routine to support database access for some application (report generation) needs.We can define a logical database to shorten our ABAP coding .
 Here I am mentioning a link which shows a complete implementation of an LDB.
http://homepages.wmich.edu/~r2raviko/HandsOnQuest/HO9.doc
 I suppose after going through the reply(or sap help) and the link mentioned above all your doubts regarding LDB will be cleared.
Thanks & Regards
Pawan P. Khilari
*Please Mark Helpful Answer

How to retrieve data using logical database and custom select options

Hi all,
I have a selection screen which is displayed by logical database PSJ and I have two select options of my own. I need to retrieve data based on both selection screen of logical database and my own select options. How can I do it?
Thanks in advance.

Hai Gupta
Check the following Document & Links
1. A logical database is in fact
a program only.
2. This LDB provides two main things :
a) a pre-defined selection screen
which handles all user inputs and validations
b) pre defined set of data
based upon the user selection.
3. So we dont have to worry about from
which tables to fetch data.
4. Moreover, this LDB Program,
handles all user-authorisations
and is efficient in all respects.
5. tcode is SLDB
good info about Logical Database. you can check the link.
http://www.geekinterview.com/question_details/1506
http://help.sap.com/saphelp_46c/helpdata/EN/35/2cd77bd7705394e10000009b387c12/frameset.htm
Re: How to Create and Use ldb in reports?
Re: Logical databases
http://help.sap.com/saphelp_46c/helpdata/en/9f/db9bed35c111d1829f0000e829fbfe/frameset.htm
Functions for displaying and changing logical databases:
Call Transaction SE36 or
Choose ABAP Workbench -> Development -> Programming environ. -> Logical databases
Interaction between database program and report:
During program processing, subroutines are performed in the database program and events are executed in the report.
To read data from a database tables we use logical database.
A logical database provides read-only access to a group of related tables to an ABAP/4 program.
advantages:-
The programmer need not worry about the primary key for each table.Because Logical database knows how the different tables relate to each other,and can issue the SELECT command with proper where clause to retrieve the data.
i)An easy-to-use standard user interface.
ii)check functions which check that user input is complete,correct,and plausible.
iii)meaningful data selection.
iv)central authorization checks for database accesses.
v)good read access performance while retaining the hierarchical data view determined by the application logic.
disadvantages:-
i)If you donot specify a logical database in the program attributes,the GET events never occur.
ii)There is no ENDGET command,so the code block associated with an event ends with the next event
statement (such as another GET or an END-OF-SELECTION).
1. transaction code SLDB.
2.enter name z<ldb-name>
3.create
4.short text
5.create
6. name of root node (here Ekko)
7. enter short text (f6)
8.node type -> data base table.
9.create
10 change logical DB
riht click on ekko and insert node
here node name ekpo
11.create
12. click on selections
13. press no Should the changed structure of Z<ldb name> be saved first.
14.select tables which you want to join.
15.transfer
16 now you have to o to coding part.
17. save
activate.
19.click to src code
double click on first include and activate
Regards
Sreeni

Selection part of Logical Database

I read about logical database somewhere on the net but it was not so clear. Can anyone explain to me about the selection part of the logical database???

Logical databases are special ABAP programs that retrieve data and make it available to application programs. The most common use of logical databases is still to read data from database tables and linking them to executable ABAP programs while setting the program contents. You edit logical databases using the Logical Database Builder in the ABAP Workbench.
However, since Release 4.5A, it has also been possible to call logical databases independently of this tool using the function module LDB_PROCESS. This allows you to call several logical databases from any ABAP program, nested in any way. It is also possible to call a logical database more than once in a program, if it has been programmed to allow this. This is particularly useful for executable programs, allowing them to use more than one logical database and process a database more than once.
Logical databases contain Open SQL statements that read data from the database. You do not therefore need to use SQL in your own programs. The logical database reads the program, stores them in the program if necessary, and then passes them line by line to the application program or the function module LDB_PROCESS using an interface work area.
http://help.sap.com/saphelp_nw2004s/helpdata/en/9f/db9b5e35c111d1829f0000e829fbfe/content.htm
A logical database is a special ABAP/4 program which combines the contents of certain database tables. You can link a logical database to an ABAP/4 report program as an attribute. The logical database then supplies the report program with a set of hierarchically structured table lines which can be taken from different database tables.
GO THROUGH LINKS -
http://www.sap-basis-abap.com/saptab.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9bfa35c111d1829f0000e829fbfe/content.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9b5e35c111d1829f0000e829fbfe/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/c6/8a15381b80436ce10000009b38f8cf/frameset.htm
/people/srivijaya.gutala/blog/2007/03/05/why-not-logical-databases
Re: **LDB**
www.sapbrain.com/FAQs/TECHNICAL/SAP_ABAP_Logical_Database_FAQ.html
www.sap-img.com/abap/abap-interview-question.htm
www.sap-img.com/abap/quick-note-on-design-of-secondary-database-indexes-and-logical-databases.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9b5e35c111d1829f0000e829fbfe/content.htm
http://help.sap.com/saphelp_nw2004s/helpdata/en/9f/db9bb935c111d1829f0000e829fbfe/content.htm
Logical databases are SAP standard programs that are desinged with selections screens that helps easy retrival and access of data from various tables in and efficient manner.
You can get to know more about the logical databases from the SAP documentation or the following links.
A logical database is a special ABAP/4 program which combines the contents of certain database tables. You can link a logical database to an ABAP/4 report program as an attribute. The logical database then supplies the report program with a set of hierarchically structured table lines which can be taken from different database tables.
Advantages of Logical database -
1) No need of programming for retrieval , meaning for data selection
2) Easy to use standard user interface, have check completeness of user input.
Disadvantages
1) Fast in case of lesser no. of tables But if the table is in the lowest level of hierarchy, all upper level tables should be read so performance is slower.
GO THROUGH LINKS -
http://www.sap-basis-abap.com/saptab.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9bfa35c111d1829f0000e829fbfe/content.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9b5e35c111d1829f0000e829fbfe/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/c6/8a15381b80436ce10000009b38f8cf/frameset.htm
1. A logical database is in fact
a program only.
2. This LDB provides two main things :
a) a pre-defined selection screen
which handles all user inputs and validations
b) pre defined set of data
based upon the user selection.
3. So we dont have to worry about from
which tables to fetch data.
4. Moreover, this LDB Program,
handles all user-authorisations
and is efficient in all respects.
5. tcode is SLDB
good info about Logical Database. you can check the link.
http://www.geekinterview.com/question_details/1506
http://help.sap.com/saphelp_46c/helpdata/EN/35/2cd77bd7705394e10000009b387c12/frameset.htm
Re: How to Create and Use ldb in reports?
Re: Logical databases
http://help.sap.com/saphelp_46c/helpdata/en/9f/db9bed35c111d1829f0000e829fbfe/frameset.htm
Functions for displaying and changing logical databases:
Call Transaction SE36 or
Choose ABAP Workbench -> Development -> Programming environ. -> Logical databases
Interaction between database program and report:
During program processing, subroutines are performed in the database program and events are executed in the report.
To read data from a database tables we use logical database.
A logical database provides read-only access to a group of related tables to an ABAP/4 program.
advantages:-
The programmer need not worry about the primary key for each table.Because Logical database knows how the different tables relate to each other,and can issue the SELECT command with proper where clause to retrieve the data.
i)An easy-to-use standard user interface.
ii)check functions which check that user input is complete,correct,and plausible.
iii)meaningful data selection.
iv)central authorization checks for database accesses.
v)good read access performance while retaining the hierarchical data view determined by the application logic.
disadvantages:-
i)If you donot specify a logical database in the program attributes,the GET events never occur.
ii)There is no ENDGET command,so the code block associated with an event ends with the next event
statement (such as another GET or an END-OF-SELECTION).
1. transaction code SLDB.
2.enter name z<ldb-name>
3.create
4.short text
5.create
6. name of root node (here Ekko)
7. enter short text (f6)
8.node type -> data base table.
9.create
10 change logical DB
riht click on ekko and insert node
here node name ekpo
11.create
12. click on selections
13. press no Should the changed structure of Z<ldb name> be saved first.
14.select tables which you want to join.
15.transfer
16 now you have to o to coding part.
17. save
activate.
19.click to src code
double click on first include and activate
Regards
Vasu

Your experience about Standby Database (Logical).

Hi,
As expressed in the subject of the thread, I'd like to get some feedback about Logical Standby.
One of the databases (A) here has a setup with a Physical Standby (B). In order to lighten the workload on A, i want to "upgrade" B to a Logical Standby. The procedure is already defined, tested and functionnal. But as I never managed a Logical Standby, it would be great if you could share your experience about:
1/ A's workload: Will there be a big overhead due to log treatments (and supplemental log data)?
2/ LAS: Will it take longer to apply an archived redo log to Logical B than it takes on the Physical B?
3/ I can't set the hardware on B's host to the same level as it's on A's host.
A has (6cpu, 20GiB RAM, half for SGA)
Physical B has (2cp, 9GiB RAM, 5GiB for SGA)
Logical B will have (3cpu, 12GiB RAM, xxxGiB SGA)
The load on B will be very very less than it is on A. Knowing A perfs is O.K., will B perf on reporting be O.K.?
4/ my target for backup is now B. When the "upgrade" will be finished, would you advise to continue the backup on the Logical Standby, or to switch to a backup via (RMAN/HotBackup/...) ?
5/ Any other advice you could give :-)
Thanks,
Yoann.

Hi Yoann,
Some time ago I created a logical database for Oracle 9.2.0.4 db on RH Linux then on 9.2.0.6 ver (same OS). It was very tempting to decrease loading on primary database through using logical standby, but It was not moved to production. I stuck with some problems when transactions stopped because of some inconsistency (I used transaction consistency set to NONE because of performance) and there were a couple of them between a hundred of tables. After that I tried to create a database link upon the primary database, but it was not apt to use with the same procedures to execute.
Regarding questions:
1. I did not find the big overhead, but a lot of additional actions should be done due to maintenance tables w/o PK on LGSTBY
2. Difficult to say ...
3. I had LGSTBY half of power of primary
4. I will not you advise to backup LGSTBY because of some possible problems with transactions, maintenance etc. better to use RMAN on primary or physical standby
5. Try to test 10g logical standby (I have read that there is no need to freeze the primary database during logical standby creation)
Hope this helps,
Andrey

Selection Screen of PNP Logical database

Experts,
I am stuck up in filtering of data.
I am using PNP logical database in Adhoc Query, if I select Current Month as data selection than also it is giving all list of data..
Can anyone give Input to me.
it is urgent.
Point will revert for useful answer.
Hetal.

how about if u do this step
1. Goto- Attribute.
2. Click "Change"
3. Click 'HR Report Category'
4. Click 'Create Report Category'
5. Click 'new entries' for careating Report Category
5. Select newly create report category
6. Click the folder 'Definition of Organizational Selection'.
7. Click 'New entries'.
8. Here you assign the required fields to be displayed, for eg pywerks - personal area.
9. finally assign this newly created 'report category' in the screen you will get upon clicking 'HR report Category' button in the Program attribute screen.
Hope this may help you. I am not much into hr abap. but sharing the info which i am aware.

Logical Database - PNP, PCH, PNPCE

Hi Experts,
Im New to ABAP HR,
I would like to know about the logical databases we are using .
Logical Database - PNP, PCH, PNPCE, basic principles
If any body cud let me know about the differences , requiremnts , associated with these Logical databses will be much helpful for me.
Thanks
Rohini Devi
[email protected]

Hi Rohini...
Global Employee Programming
Thanks
Message was edited by:
Aslam Riaz

ABAP Logical Database ADA

Hi All, I am quite familiar with Logical Databases but I need to understand the following.
1) I am using LDB ADA, but I want to use my own Selection Screen and not the default one that the LDB provides. I know I must put something in AT SELECTION-SCREEN but am unsure what.
2) Once I get the data, I want to store the data in an internal table - how do I go about doing this? If you can provide a code example that would be great.
Points for any relevant help.

Hi,
A logical database is a special ABAP/4 program which combines the contents of certain database tables. You can link a logical database to an ABAP/4 report program as an attribute. The logical database then supplies the report program with a set of hierarchically structured table lines which can be taken from different database tables.
Logical database structures
There are three defining entities in an SAP logical database. You must be clear on all three in order to create and use one.
Table structure: Your logical database includes data from specified tables in SAP. There is a hierarchy among these tables defined by their foreign keys (all known to SAP), and you are going to define a customized relationship between select tables. This structure is unique and must be defined and saved.
Data selection: You may not want or need every item in the referenced tables that contributes to your customized database. There is a selection screen that permits you to pick and choose.
Database access programming: Once youve defined your logical database, SAP will generate the access subroutines needed to pull the data in the way you want it pulled.
Creating your own logical database
Heres a step-by-step guide:
1) Call up transaction SLDB (or transaction SE36). The path you want is Tools | ABAP Workbench | Development | Programming Environment | Logical Databases. This screen is called Logical Database Builder.
2) Enter an appropriate name in the logical database name field. You have three options on this screen: Create, Display, and Change. Choose Create.
3) Youll be prompted for a short text description of your new logical database. Enter one. Youll then be prompted to specify a development class.
4) Specify a root node, or a parent table, as the basis of your logical database structure. You can now place subsequent tables under the root table as needed to assemble the data object you want. You can access this tree from this point forward, to add additional tables, by selecting that root node and following the path Edit | Node | Create. Once youve saved the structure you define in this step, the system will generate the programming necessary to access your logical database. The best part is you dont have to write a single line of code.
Noted point is we cant add any selection criteria thru our se38 program if you are attaching any LDB to program.Ist of no use.
If you want to change selection criteria to the existing LDB, you have to goto SE36 tcode and provide LDB name and choose "Change" mode by selecting "Selections" Radio button.
declaration of params is different compared to normal se38 program in some aspects.
PARAMETERS :p_curr LIKE bkpf-waers FOR TABLE bkpf OBLIGATORY.
this BKPF table should be one of the node in the "Structure" Radio button.
Thanks
Sivaparvathi
Please reward points if helpful.

Transporting Views created for Logical Database in QAS

Hello all,
Can anybody let me know teh steps...
How to transport views created for logical database from dev to QAS...
kindly give the steps...
thanks
saurabh

I don't think PNPCE does anything with HRP infotypes. PNPCE is all about PA data since PERNR is the main key. Logical DB PCH is the one that deals with HRP Infotypes.

Steps to create LOGICAL DATABASE in sap

hi guys,
i have gone through many documents about LDB. But, i didnt get the steps to create a LDB.
plz provide me with the steps to be followed to create a LDB.
thnx,
shivaa.

Hi Shiva,
This might help you!
Logical database structures
There are three defining entities in an SAP logical database. You must be clear on all three in order to create and use one.
Table structure: Your logical database includes data from specified tables in SAP. There is a hierarchy among these tables defined by their foreign keys (all known to SAP), and you are going to define a customized relationship between select tables. This structure is unique and must be defined and saved.
Data selection: You may not want or need every item in the referenced tables that contributes to your customized database. There is a selection screen that permits you to pick and choose.
Database access programming: Once youu2019ve defined your logical database, SAP will generate the access subroutines needed to pull the data in the way you want it pulled.
Creating your own logical database
ABAP/4 (Advanced Business Application Programming language, version 4) is the language created by SAP for implementation and customization of its R/3 system. ABAP/4 comes loaded with many predefined logical databases that can construct and table just about any conventional business objects you might need in any canned SAP application. However, you can also create your own logical databases to construct any custom objects you care to define, as your application requires in ABAP/4. Hereu2019s a step-by-step guide:
1. Call up transaction SLDB (or transaction SE36). The path you want is Tools | ABAP Workbench | Development | Programming Environment | Logical Databases. This screen is called Logical Database Builder.
2. Enter an appropriate name in the logical database name field. You have three options on this screen: Create, Display, and Change. Choose Create.
3. Youu2019ll be prompted for a short text description of your new logical database. Enter one. Youu2019ll then be prompted to specify a development class.
4. Now comes the fun part! You must specify a root node, or a parent table, as the basis of your logical database structure. You can now place subsequent tables under the root table as needed to assemble the data object you want. You can access this tree from this point forward, to add additional tables, by selecting that root node and following the path Edit | Node | Create. Once youu2019ve saved the structure you define in this step, the system will generate the programming necessary to access your logical database. The best part is you donu2019t have to write a single line of code.
Watch out!
The use of very large tables will degrade the performance of a logical database, so be aware of that trade-off. Remember that some tables in SAP are very complex, so they will be problematic in any user-defined logical database.
Declaring a logical database
Hereu2019s another surprising feature of logical databases: You do not assign them in your ABAP/4 Code. Instead, the system requires that you specify logical databases as attributes. So when you are creating a report, have your logical database identifier (the name you gave it) on hand when you are defining its attributes on the Program Attributes screen. The Attributes section of the screen (the lower half) will include a Logical database field, where you can declare your logical database.
Logical databases for increasing efficiency
Why else would you want to create a logical database? Consider that the logical databases already available to you begin with a root node and proceed downward from there. If the data object you wish to construct consists of items that are all below the root node, you can use an existing logical database program to extract the data, then trim away what you donu2019t want using SELECT statementsu2014or you can increase the speed of the logical database program considerably by redefining the logical database for your object and starting with a table down in the chain. Either way, youu2019ll eliminate a great deal of overhead.
Reward if useful.
Thankyou,
Regards.

What exactly are Logical Database in Programs?

Hi Experts,
While digging deep into the programs, using the T-Code SE93/SE38, we come across Logical Database.
what is the functionality and use of this Logical Database?
Best Regards,

Normally moderators reject unresearched questions, but this one has not been discussed much for it's security aspects.
In the ABAP forums you will find a lot of discussions about LDB's ("LDB" is your search term).
Please do a search and reconsider and focus your question more.
What is it about LDB's that you would like to discuss?
Cheers,
Julius

Logical Database design and physical database implementation

Hi
I am an ORACLE DBA basically and we started a proactive server dashboard portal ,which basically reports all aspects of our infrastructure (Dev,QA and Prod,performance,capacity,number of servers,No of CPU,decomissioned date,OS level,Database patch level) etc..
This has to be done entirely by our DBA team as this is not externally funded project.Now i was asked to do " Logical Database design and physical Database
implementation"
Even though i know roughly what's that mean(like designing whole set of tables in star schema format) ,i have never done this before.
In my mind i have a rough set of tables that can be used but again i think there is lot of engineering involved in this area to make sure that we do it properly.
I am wondering you guys might be having some recommendations for me in the sense where to start?are there any documents online , are there any book on this topic?Are there any documents which explain this phenomena with examples ?
Also exactly what is the difference between logical database design vs physical database implementation
Thanks and Regards

Logical database design is the process of taking a business or conceptual data model (often described in the form of an Entity-Relationship Diagram) and transforming that into a logical representation of that model using the specific semantics of the database management system. In the case of an RDBMS such as Oracle, this representation would be in the form of definitions of relational tables, primary, unique and foreign key constraints and the appropriate column data types supported by the RDBMS.
Physical database implementation is the process of taking the logical database design and translating that into the actual DDL statements supported by the target RDBMS that will create the database objects in a target RDBMS database. This will generally include specific physical implementation details such as the specification of tablespaces, use of specialised indexing (bitmap, clustered etc), partitioning, compression and anything else that relates to how data will actually be physically stored inside the database.
It sounds like you already have a physical implementation? If so, you can reverse engineer this implementation into a design tool such as SQL Developer Data Modeller. This will create a logical design by examining the contents of the Oracle data dictionary. Even if you don't have an existing database, Data Modeller is a good tool to use as a starting point for logical and even conceptual/business models.
If you want to read anything about logical design, "An Introduction to Database Systems" by Date is always a good starting point. "Database Systems - A Practical Approach to Design, Implementation and Management" by Connolly & Begg is also an excellent reference.

Regarding Logical database and select statement..

Hi
Experts.
i would like to know the diff b/w logical data base & select statement while using report.
wt is the use of logical databases in R/3. is there   any   advantage used in the reports.
Thanks & Regards..
Spandana.

Dear Spandana,
Go through the below description of LDB. I hope you wil get a fair amount of idea.
SAP comes loaded with all the extras. Among the extras that are most helpful to IT managers are all the access routines needed to pull any business object that managers can think of out of SAP databases. However, SAP has not thought of everything where your particular applications are concerned. SAP organizes its standard database tables to service business units based on conventional business applications. Itu2019s likely your business requires something new, perhaps even something exotic. In that case, you will need to create a new database, using information from different places. Basically, you need a logical database. You need to create a virtual business data object repository consisting of a new kind of record or table that suits your purposes. In addition, the repository should be composed of information that is actually stored in a number of different locations, none of them necessarily logically associated with one another. Letu2019s take a closer look at creating logical databases.
A case for a logical database
Suppose my company manufactures widgets of the most obscure variety, and they are components of other widgets. I sell my widgets as raw material for the more sophisticated widgets built by others, but in some cases I actually partner with other manufacturers in creating yet another class of widget. Now, in my world, I consequently have customers who are also partners. I sell to them and I partner with them in manufacturing and distribution. Also, I need an application that uses both of these dual-use relationships.
Essentially, I have a customer database and a partner database. Neither contains records that are structured to contain the identifying particulars of the other. Thus, I need a hybrid database that gives me tables detailing these hybrid relationships. What can I do? I can go the long way around and write a new database, pulling information from both and creating new objects with a customized program that I write by hand. However, this process is cumbersome and contains maintenance issues. On the other hand, I can use SAPu2019s logical database facility, create my logical database in a couple of minutes, and have no maintenance issues at all.
Logical database structures
There are three defining entities in an SAP logical database. You must be clear on all three in order to create and use one.
u2022     Table structure: Your logical database includes data from specified tables in SAP. There is a hierarchy among these tables defined by their foreign keys (all known to SAP), and you are going to define a customized relationship between select tables. This structure is unique and must be defined and saved.
u2022     Data selection: You may not want or need every item in the referenced tables that contributes to your customized database. There is a selection screen that permits you to pick and choose.
u2022     Database access programming: Once youu2019ve defined your logical database, SAP will generate the access subroutines needed to pull the data in the way you want it pulled.
Creating your own logical database
ABAP/4 (Advanced Business Application Programming language, version 4) is the language created by SAP for implementation and customization of its R/3 system. ABAP/4 comes loaded with many predefined logical databases that can construct and table just about any conventional business objects you might need in any canned SAP application. However, you can also create your own logical databases to construct any custom objects you care to define, as your application requires in ABAP/4. Hereu2019s a step-by-step guide:
1.     Call up transaction SLDB (or transaction SE36). The path you want is Tools | ABAP Workbench | Development | Programming Environment | Logical Databases. This screen is called Logical Database Builder.
2.     Enter an appropriate name in the logical database name field. You have three options on this screen: Create, Display, and Change. Choose Create.
3.     Youu2019ll be prompted for a short text description of your new logical database. Enter one. Youu2019ll then be prompted to specify a development class.
4.     Now comes the fun part! You must specify a root node, or a parent table, as the basis of your logical database structure. You can now place subsequent tables under the root table as needed to assemble the data object you want. You can access this tree from this point forward, to add additional tables, by selecting that root node and following the path Edit | Node | Create. Once youu2019ve saved the structure you define in this step, the system will generate the programming necessary to access your logical database. The best part is you donu2019t have to write a single line of code.
Watch out!
The use of very large tables will degrade the performance of a logical database, so be aware of that trade-off. Remember that some tables in SAP are very complex, so they will be problematic in any user-defined logical database.
Declaring a logical database
Hereu2019s another surprising feature of logical databases: You do not assign them in your ABAP/4 Code. Instead, the system requires that you specify logical databases as attributes. So when you are creating a report, have your logical database identifier (the name you gave it) on hand when you are defining its attributes on the Program Attributes screen. The Attributes section of the screen (the lower half) will include a Logical database field, where you can declare your logical database.
Logical databases for increasing efficiency
Why else would you want to create a logical database? Consider that the logical databases already available to you begin with a root node and proceed downward from there. If the data object you wish to construct consists of items that are all below the root node, you can use an existing logical database program to extract the data, then trim away what you donu2019t want using SELECT statementsu2014or you can increase the speed of the logical database program considerably by redefining the logical database for your object and starting with a table down in the chain. Either way, youu2019ll eliminate a great deal of overhead.
Regards
Arindam

Logical Database PNP cannot fetch correct data?

I use logical database PNP fetch HR master data.
PA0001 has records with company code = 0960 .
But can not fetch data using GET PERNR.
however
PA0001 has not records with company code = 0770 .
But it got so many data using GET PERNR.
WHY..............
person originally transferd from 0770 to 0960, It is OK.

I belive this is not concurent employment why we need to use
PNPCE
Please be specific about your question
Regards

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