Goto the transaction code SE36 ( Logical database Builder) and enter the logical database name and click on the CREATE button.
We need to have structure, selections and source code.
Enter the short text and click on the CREATE button.
In order to create the structure, Enter the short text for the root node and the corresponding table and click on the CREATE button.
Give the second node which should be hierarchically under the root node and enter the short description with the database table name .
Now click on the SELECTIONS buttons and u need to have the selections of logical database be generated from the structure and do not define a new search help.
U get the menu generation options. Select the tables for which the nodes for the free selections are to be generated.
Uncomment the select options for both the tables and SAVE, CHECK & ACTIVATE.
Now click on the SOURCE CODE button and should generate the program of the logical database from structure and selections.
Double click on the TOP INCLUDE structure.
Check whether the tables used in the logical database are present and uncommented and click BACK.
Now double click on the system routines include structure.
In the system routines, double click on the INCLUDE structure of NODE ZKA_EMP. Now uncomment the SQL statement and enter the field and the database table name according to the logical database builder.
Click BACK and In the system routines, double click on the INCLUDE structure of NODE ZKA_COM. Now uncomment the SQL statement and enter the field and the database table name according to the logical database builder
SAVE, CHECK and ACTIVATE the screen.
Click BACK and SAVE, CHECK & ACTIVATE the screen until u reach the main screen and SAVE the logical database.
Thus the logical database is constructed.
Also See : What is Logical Database?Logical database in ABAP programming