Data extract function overview

The data extract function offers flexible, generalized segment selection and data extraction facilities. Selected segments and/or data items can be written to a sequential data set for subsequent processing by a user-written program.

How extract works

Fast Path Analyzer/EP completes a data extract that is based on how you combine the EXTRACT command with its associated keywords and subcommands. This command syntax defines the inputs to the extract process and the outputs from the extract process.

Format flexibility

The EXTRACT command is versatile and powerful.

You can extract as much or as little data as you want from a DEDB. The format and content of the outcome (the extract output file) can be controlled by specifying a user-customized combination of command syntax.

Input flexibility

The data extract function lets you select the database and areas within the database to be used as input to the extract. You can use the DEDB or an image copy of a DEDB as input. The data extract function also lets you include or exclude certain segments for processing.

Output format flexibility

Extracted data is written to an output file by using one of three user-selectable output formats.

The format that you select dictates the extent to which you can exercise control over the database-level and area-level header and trailer records and the content of the segment data records (including segment prefixes and suffixes).

• If the application that reads the extract data does not have specific formatting requirements, or if those requirements have not yet been determined, the default format (EXTRACT) should be used. A module is provided with Fast Path Analyzer/EP to facilitate reading the extracted data from a user-written program. For instructions about using this module, see the Fast Path/EP Series Reference Manual documentation . For a sample COBOL program to retrieve extracted data, see the member PFUGXDR in the Fast Path/EP sample library.

• The data can be written in the same format (HDUNLOAD) as the Fast Path Reorg/EP unload function. This format should be used when the extracted data is used as input to the reload process.

• The data can be written in a custom-tailored format (USER). This format should be used when an existing application program requires extracted data in a specific format.

Benefits

The data extract function provides the following benefits:

• It increases productivity of application programmers by extracting data, using a control statement-driven, generalized, high-speed utility.

• It provides a convenient mechanism for creating test databases. Specified database records can be unloaded easily from a production database and reloaded to a test database.

• It eliminates IMS overhead because BMPs are not required.