What is logical Data base

The LDB is special type of ABAP program that combines the contents of certain related database tables and retrieve some related data and make it available to application programs.
In other words, a LDB is a method by which ABAP programs read and process the data. The sequence in which the data is supplied to the program is determined by a tree structure.

LDB Components
Structure
Selections
Database program

Features
Logical databases have a tree structure.
A logical database can contain a maximum of 300 tables
SAPDBPNP is the name of the database program for the logical database PNP.
SE36 is the Transaction code for the LDB creation.

LDB Events

GET node

This statement defines an event block whose result is triggered by the ABAP runtime environment after submitting an executable program.
If the logical database to which the program is linked, provides data in the work area node. The node work area must be declared with the NODES statement (or TABLES).

The data can be processed in the event block
Different LDB’s for HR module
Organizational Management - PCH
Personnel Administration - PNP or PNPCE
Recruitment - PAP
Personnel Development - PCH
Time Management - PNP
Training and Event Management - PCH
Functions of LDB
1. Data retrieval
The personnel data of each employee is loaded into the main memory where it can be accessed for processing
2. Screening
Employees will be filtered as per the data selection period and the personal selection period from the LDB selection screen
3. Authorization checks
This ensures that the person starting the evaluation Is authorized to access the report data.

HR Report category
Used for HR reports that use the PNP logical database.
It controls the type and number of fields that appear on the selection screen of an evaluation report. HR Report category and the LDB name for an abap program will be provided as attributes information. we have sufficient standard report categorys provided for each LDB and we can even create report categorys as and how we want.