Open data path considerations

 

An open data path (ODP) is a control block created when a file is opened. An ODP contains information about the merged file attributes and information returned by input or output operations.

The file, library, and file member names used by ODP are the same as the first file and file member names specified on the FILE parameter, unless an override forces the use of a different file or file member name. The record format name of the open query file is the same as that specified on the FORMAT parameter.

The Open Query File (OPNQRYF) command always opens a file with an ODP that is shared, as if SHARE(*YES) were specified for the file. If the file, library, or file member name specified in the high-level language (HLL) program differs from the name of the open query file, an override command must be used to specify the correct file, library, and member names to allow the HLL program to share the open query file ODP. If the first, or the only, member queried has an attribute of SHARE(*NO), SHARE(*YES) must be specified in an override to enable an HLL program to share the query file ODP.

If the OPNQRYF command is scoped to the job, any subsequent open, other than a query open, of the same file can share the ODP whether scoped to an activation group or the job. If the OPNQRYF command is scoped to an activation group, any subsequent open, other than a query open, of the same file can share the ODP if it is also scoped to the same activation group.

 

Parent topic:

Using Open Query File (OPNQRYF) command