Online data extract function overview

The Fast Path Online Analyzer/EP online data extract function provides an excellent alternative to user-written batch message processing programs (BMPs) for extracting segment data (full or partial segments) from DEDBs while they are online to IMS. The online 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.

Because Fast Path Online Analyzer/EP incorporates all batch functionality that is provided by the Fast Path Analyzer/EP product, you can also perform an offline data extract by using Fast Path Online Analyzer/EP.

For information about performing offline data extracts, see the Fast Path Offline Suite documentation.

Format flexibility

The EXTRACT command is versatile and powerful.

While the database is online, 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 online data extract function lets you select the database and areas within the database to be used as input to the extract. The online data extract function also lets you include or exclude certain segments for processing.

Output 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 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 how to use 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 might 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 might 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 online data extract function provides the following benefits:

It increases productivity of application programmers by extracting data, using a control statement-driven, generalized, high-speed online utility.
It does not affect database availability. The EXTRACT command accesses a DEDB with logical database record integrity while the database is being updated by IMS.
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.
It provides full multiple area data set (MADS) usage.