non-virtual property

[ConvertFromOldNGs]

by micc >> Sun, 14 Sep 2008 20:08:18 GMT

Dear Jade User

Hi

I am interesting about Database Reorganization.
And I have a question .. what is non-virtual property ?
( as stated in White Paper - Schema Evolution - page 15 )

Thanks for your information

[ConvertFromOldNGs]

by Dean Cooper >> Sun, 14 Sep 2008 21:00:22 GMT

A non-virtual property (either an attribute or a reference) is one that exists physically on an object. Most properties in a system are non-virtual (that is, the Virtual checkbox in either the Define Attribute or Define Reference dialog is not checked). When you select a property in the IDE, it will show either "non-virtual" or "virtual" in the details panel of the Class Hierarchy Browser to indicate what kind of property it is.

Virtual properties are implemented entirely by a mapping method and have no space allocated for them in the object. So a virtual property allows you to write a (mapping) method that developers can access as though it were a property. That is:

virtProp := someValue;

will invoke the "set" operation of your mapping method, and:

write virtProp;

will invoke the "get" operation of your mapping method. Typically the mapping method behind your virtual property will get/set other property values in your application.

Dean.