Maintaining Your Data Model › Creating User-Defined Field Types › Example: Defining a Century date Field Type (DTX)

Example: Defining a Century date Field Type (DTX)

This example shows how to define a century date field data type (DTX). Since the shipped DT# field type has the capabilities defined here, use this example only to understand the steps needed to define your own field type. The DTX field type is to have the following characteristics.

• Internal format packed numeric: CCYYMMDD, fixed length
• External display format numeric: DD/MM/CCYY, fixed length
• Value mapping to convert between the internal and external values
• Validation to check that entered dates are valid

The first step is to define the mapping functions needed for the DTX field type.

Type P next to the Check DTX and Convert DTX to display their parameters. Press Enter.