Logical database
A logical database is a special ABAP/4 program which combines the contents of certain database tables. Using logical databases facilitates the process of reading database tables.

HR Logical Database is PNP

Main Functions of the logical database PNP:

• Standard Selection screen
• Data Retrieval
• Authorization check
  

To use logical database PNP in your program, specify in your program attributes.

Standard Selection Screen

• Date selection
  Date selection delimits the time period for which data is evaluated. GET PERNR retrieves all records of the relevant infotypes from the database.  When you enter a date selection period, the PROVIDE loop retrieves the infotype records whose validity period overlaps with at least one day of this period.
• Person selection
  Person selection is the 'true' selection of choosing a group of employees for whom the report is to run.
• Sorting Data
  · The standard sort sequence lists personnel numbers in ascending order.
  · SORT function allows you to sort the report data otherwise. All the sorting fields are from infotype 0001.
• Report Class
  · You can suppress input fields which are not used on the selection screen by assigning a report class to your program.
  · If SAP standard delivered report classes do not satisfy your requirements, you can create your own report class through the IMG.

Data Retrieval from LDB

1. Create data structures for infotypes.

    INFOTYPES: 0001, "ORG ASSIGNMENT
                        0002, "PERSONAL DATA
                        0008. "BASIC PAY

2. Fill data structures with the infotype records.

    Start-of-selection.
         GET PERNR.
    End-0f-selection. 

    Read Master Data

• Infotype structures (after GET PERNR) are internal tables loaded with data.
• The infotype records (selected within the period) are processed sequentially by the PROVIDE - ENDPROVIDE loop.

          GET PERNR.
             PROVIDE * FROM Pnnnn BETWEEN PN/BEGDA AND PN/ENDDA
                    If Pnnnn-XXXX = ' '. write:/ Pnnnn-XXXX. endif.
             ENDPROVIDE.

• Period-Related Data
  All infotype records are time stamped.
  
  IT0006 (Address infotype)
  01/01/1990   12/31/9999  present

          Which record to be read depends on the date selection period specified on the
          selection screen. PN/BEGDA PN/ENDDA.

• Current Data 
  IT0006 Address  -  01/01/1990 12/31/9999   present

Related Items:

• ABAP Infotypes
• Download Employee Data
• Employees by zip code
• How can I 'advance in dialog'
• HR Logical Database