MetaProperty

Basics

In UBIK, a MetaProperty describes a single feature of a certain MetaClass. A MetaProperty will never hold own values, but it serves as a definition for a resulting BaseProperty on a derived ContentClass.

For enhanced reuse, MetaProperties can be organized in a Pool and linked to many MetaClasses, using the Systemrelation MetaProperty

Initial value

The initial value of a MetaProperty defines which value will be set to the property initially when a new instance of it is created. Once the value is changed, the initial value is lost for this instance.

Default value

The default value of a MetaProperty defines which value will be delivered by a property if it doesn't have an own value set.

Editing a MetaProperty

Once a MetaProperty is used on a single MetaClass editing of properties is restricted to properties that may not effect data validity. The System uses a Rule to validate the edited properties and creates a RuleViolation whenever a "locked" property is edited. Following properties may not be changed/edited for a "used" MetaProperty:

Name
PropertyType

Released To LiveMode

A MetaProperty is marked as released to live mode when:

It is used on at least one MetaClass which is already released.
It is referenced by at least one PoolMetaProperty which is used on at least one MetaClass which is already released.

Editing a released MetaProperty is restricted to properties that have no effect on the released table structure. The System uses a Rule to validate the edited properties and creates a RuleViolation whenever a "locked" property is edited. Following properties may not be changed/edited for a released MetaProperty:

Name
PropertyType
StringLen
Multilanguage
Indexcount
Serialize
NeedsValidation
IndexType