Modifying Function Parameters › Identifying the Basic Properties › Positioner Parameter

Positioner Parameter

This parameter is used to position a function to start reading records from a database file at a particular record. Positioner parameters can be used by themselves or in conjunction with restrictor parameters. They must be key fields on the access path to which their function attaches and can only be used hierarchically.

For example, a minor key can only be a positioner parameter if all major keys to it are also positioner or restrictor parameters. Positioner parameters are automatically mapped and can be either Output or Both on the panel.

The following table is an example of the use of positioner parameters.

FIL   Company   REF   Known By   FLD   Company code     CDE
FIL   Company   REF   Has        FLD   Company name     TXT

FIL   Division  REF   Owned by   REF   Company          FIL
FIL   Division  REF   Known By   FLD   Division code    CDE
FIL   Division  REF   Has        FLD   Division name    TXT
FIL   Division  REF   Has        FLD   No of employees  NBR

If you define a PRTFIL function based on a retrieval access path over the division file (such as, with keys Company Code and Division Code fields) and if you want to specify selection you could either:

• Make both Company Code and Division Code positioner parameters in order to read all records starting at specified values for both key fields
• Make Company Code a restrictor but Division Code a positioner parameter in order to read all records for a specified Company file starting at a given division