IBM® Informix® 12.10

The HPL data-unload process

The data-unload process is essentially the same as the load process, but in reverse. The data-unload process extracts the source data from one or more database tables; converts the data to a new format; and writes the converted data to a file, tape, or on UNIX to a pipe (application). As in a load, you can manipulate the data from a database table so that the converted data displays different characteristics.

The following figure shows how the components of the High-Performance Loader (HPL) affect the data as it moves from a database to data files during the unload process. The HPL uses:

The query to select records from the database
The map to reorganize or modify the selected records
The format to prepare the records for writing out to the data files
The device array to find the location of the data files

Figure 1. The data-unload process

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The HPL uses the same components for an unload job as for a load job, with one exception. For an unload job, ipload creates a Structured Query Language (SQL) query that extracts selected data from the table. As with a load, unload components are grouped together into an unload job. Unload jobs can be saved, retrieved, and rerun as many times as necessary. Unload jobs can be grouped together with load jobs in the same project.

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To find the PDF, see Publications for the IBM Informix 12.10 family of products.
For the release notes, documentation notes, and/or machine notes, see the Release Notes page.

Release date: March 2013