Modifying Function Parameters › Identifying the Basic Properties › Understanding the Role of the Parameter › Restrictor Parameter

Restrictor Parameter

This parameter is used to restrict the records from a database file that can be displayed, changed, or printed by the function. Restrictor parameters must be key fields on the access path to which their function attaches and can only be used hierarchically; that is, major to minor key sequence.

A minor key can only be a restrictor parameter if all keys major to it are also restrictor parameters. Restrictor parameters are automatically mapped and default to output on the panel, but may be changed to input on DSPFIL, SELRCD, and EDTFIL function types.

For example, a function that displays a list of records (such as DSPFIL) could allow the user to select a particular record with a line selection option. The keys of the selected record could be passed as restrictors to another function (such as EDTRCD). The called function then process only the selected record.