Extended data types

Extended data types (EDTs) have a rich extension model that lets extenders change specific behaviors.

To provide an extensible solution, keep the following guidelines in mind when you work with EDTs.

Label/Help text

Labels and Help text properties can be changed by an extension, but only one value can remain. If multiple solutions change the label of the same EDT, the various labels are, in functional terms, mutually exclusive. Therefore, those labels can't all be installed on the same system.

String size

String size can be defined only on root EDTs. The system will use the largest value that is defined across the EDT and its extensions.

For derived EDTs, string size can't be changed by an extension, because the IS-A relationship between the EDTs will be broken.

Assignments to string EDTs will truncate the string to match the defined string size.


The extends property can't be changed by an extension. Any change that is made to this property after release will cause a breaking change. Therefore, you must make sure that the property is set correctly before release.

If you set this property, neither you nor extenders will be able to make changes to the string size later.

Avoid unnecessary dependencies. For example, don't extend generic EDTs such as Name and Description.

Number of decimals

The Number of decimals property can't be changed by an extension.

If you set this property to True, extenders can change the number of decimal places.

If you set this property to True, make sure that the following conditions are met:

  • All truncation logic honors the number of decimal places that is specified on the EDT, so that no implicit or hardcoded rounding will occur.
  • The value isn't assigned to other incompatible EDTs that don't correctly handle rounding.