For the random-by-key method of processing, you specify a search argument that identifies the key of the record to be read in factor 1 of the calculation specifications for the CHAIN operation. See the section on "Keyed Processing Examples" in Chapter 7 of the RPG/400* User's Guide for an example of an externally described DISK file being processed randomly by key. The specified record can be read from the file either during detail calculations or during total calculations.
The random-by-key method of processing is valid for a full-procedural file designated as an input file or an update file.
For an externally described file, position 31 of the file description specifications must contain K, which indicates that the file is processed according to an access path that is built on keys. The data description specifications for the file specifies the field that contains the key value (the key field). Position 32 of the file-description specifications must be blank.
You must designate a program-described file as an indexed file (I in position 32), and position 31 of the file-description specifications must contain an A or a P. The length of the key field is identified in positions 29 and 30 of the file-description specifications, and the starting location of the key field is identified in positions 35 through 38. Data description specifications must be used to create the access path for a program-described input file. Refer to the section "Indexed File" in chapter 7 of the RPG/400* User's Guide.
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