‎2007 Oct 29 9:32 AM
Hi,
What is Logical Database? advantages and disadvantages?
thanks in advance?
‎2007 Oct 29 9:34 AM
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.
adv:-
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.
disadv:-
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).
reward if useful
‎2007 Oct 29 9:36 AM
ANS:-<b> To read data from a database tables we use logical database</b>.
A logical database provides read-only access to a group of related tables to an ABAP/4 program.
<b> adv:-</b> 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
<b>. disadv:-</b> 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
‎2007 Oct 29 9:37 AM
Hi,
Advantages of Using Logical Databases
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db99b435c111d1829f0000e829fbfe/content.htm
Logical databases save you having to define a selection screen and read data from the database in every program. The program does not have to specify how to retrieve the data, but instead only has to process it and display it on the screen.
An executable program can only work with one logical database, but each logical database can be used by several programs. This offers considerable advantages over integrating the database accesses with SELECT statements into each executable program. It means that you only have to code identical access paths once. The same applies to coding authorization checks.
When you use logical databases, most executable programs benefit from having
· an easy-to-use and standard user interface
· check functions, which check that user input is complete, correct, and plausible
· meaningful data selection
· central authorization checks for database accesses
· good read access performance (for example, with views) while retaining the hierarchical data view determined by the application logic.
Even though you are using central logical databases, the program itself remains flexible because:
· You can still create your own selection screens for each program
· You can code your own functions in any event block in the program. For example, you may want to write user dialogs for further authorization or plausibility checks on the selection screen.
+++++
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9b5e35c111d1829f0000e829fbfe/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/9f/db9bed35c111d1829f0000e829fbfe/frameset.htm
Thanks,
Aby
‎2007 Oct 29 9:42 AM
Each logical database is an encapsulated data collection program for frequent database access.
Database access has been optimized using Open SQL.
If you are working with a logical database, you do not need a selection screen for user entry, because
it is created automatically.
The system performs authorization checks according to the SAP authorization concept.