<CONTEXT_FIELD> : Context field

ROLE

This element should refer to another RELATION field that belongs to the same class as the current field. This field creates a context that limits the list of available objects in the current field. Only objects that are related to those selected into the context field are available for the current field. Those relations between objects are computed with a cross-reference mechanism.

ATTRIBUTES

<!ATTLIST CONTEXT_FIELD
	  idref IDREF #REQUIRED>
Attribute Mand. Description Default
idref yes Identifier of the relation field used to define the context of the relation.  

SAMPLE

For example, consider a class Contract that has two relation fields.
The first relation field is named firm and refers to objects of the Firm class.
The second relation is named department and refers to objects of the Department class.
On the other hand, a relation on the Department class refers to an object
of the Firm class and then defines the firm to which a department belongs.

<RELATION id="firm">
...
	<CLASSES idrefs="Firm"/>
...
</RELATION>

<RELATION id="department">
...
	<CLASSES idrefs="Department"/>
	<CONTEXT_FIELD idref="firm"/>
...
</RELATION>

The context field defined inside the department field ensure that only departments
that belong to the selected firm are offered to selection to the user.