HP 3000 Manuals

HP ALLBASE/BRW Reference Manual

Using Output Files 

There are several ways that you can use the different types of output
files described in this chapter.  The following sections describe some
suggestions and examples.

Database ExtractFiles 

A database extract file contains a subset of data from a database.

Database extract files allow faster access to:

   *   a subset of the data in databases

   *   a summary of the data in databases

   *   data calculated from data in databases

   *   a combination of these for reports and other programs

Database extract files can be:

   *   intermediate report files, if only HP ALLBASE/BRW reports access
       the file

   *   dictionary output files if other programs also access the file

Example 

Suppose you have a large database of order information, and want to
report on orders for certain products only.  You can define an HP
ALLBASE/BRW report that reads the database and creates an output file
containing only data for the certain products required.  This output file
contains an extract of the data in the database, hence the name database
extract file.  You can then create reports and use the data from the
output file as the source table for the reports.  In this way, only one
report needs to read the large database and performance is improved,
especially if the report that produces the extract file is run overnight.

The following diagram shows how database extract files work:


            

MPE/iX 5.0 Documentation