ABAP FAQ - Logical Databases

 LOGICAL DATABASE.

What are logical databases?  What are the advantages/disadvantages of logical databases?

Ans :- A Logical Database is a hierarchical structure of tables. Use the GET statement to process Logical Databases.

- LDB consists of logically related tables grouped together – used for reading and processing data.

- Advantages = 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.

Preparation of the data records by  the L.D.B  and reading of the data records in the actual report are accomplished with the command pair.

- Put and Get.

The three main elements of  LDB are  

- Structure, Selections, Database Program.

What sort of tables one can use in designing the hierarchy of  a  LDB ?

- Tables which are having Foreign key relations.

The structure of Logical Databases relfects the ________________   dependencies of hierarchical tables in the SAP System.

- Foreign key

If you want to improve the response time ( time to access data ) Logical DataBases permits you  to achieve this using  ______________

- VIEWS.

What are the advantages of  Logical DataBases ?

- It offers an easy-to-use selection screen.                                                       You can modify the pre-generated selection screen to your needs.                        It offers check functions to check whether user input is complete, correct, and plausible.              It offers reasonable data selections.           It contains central authorization checks for database accesses. Enhancements such as improved performance immediately apply to all report programs that use the logical database.