Maintaining Your Data Model › Creating User-Defined Field Types › Defining the Mapping Functions

Defining the Mapping Functions

Having specified the parameters for the Check DTX and Convert DTX functions, you can describe the internal processing of the functions themselves, using an action diagram of type Execute Internal Function. The Check DTX function would do the following:

1. Check that the date entered is a valid date of the form DDMMCCYY.
2. Convert the external value of the DTX field, in DDMMCCYY format, into the internal value, in CCYYMMDD format.

The Convert DTX function has only to convert the internal value of the field, in CCYYMMDD format, to the external value, in DDMMCCYY format.