Inheritance of Domain Properties

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When you define a domain, you can indicate that the domain has a superdomain. If a domain has a superdomain, domain properties are inherited from that superdomain following certain rules. This section describes how a subdomain inherits properties from its superdomain.

Always inherited

The following properties of superdomains are always inherited by their subdomains, or by columns defined on them. These properties cannot be changed at the subdomain level:

· Data Type


· Column Width (see the Note below)


· Decimals


· Decimals Displ.


· Uppercase


· Fixed Length

Furthermore, if you define a domain constraint for a superdomain, this constraint is also executed for the subdomains.


Some data types do not allow you to define a column width (e.g. CLOB, INT, DATE, LONG, LONGRAW). In that case, these properties cannot be inherited. (If you cannot define something at the superdomain level, it cannot be defined at the subdomain level either.)

Inherited if defined for superdomain

The following properties are only inherited if they have been defined at the superdomain level. If the corresponding fields have been left empty at the superdomain level, you can still define them at the subdomain level:

· IO Format


· Min. Value


· Max. Value

Inherited, but can be overruled

The following properties are inherited, but can always be overruled at the subdomain level:

· Default Value


· Help Text


· Description


· Display Length


· Display Type


· Generate Unique Values

Not inherited

Allowed Values, Alternative Input Formats, and Comments defined for a superdomain are not inherited by subdomains.