Bug 181121 Model should provide utility method for cube to get correspond dimension key.
In model cube handle, the relation of cube data set and dimension data sets are managed by a series of dimension condition handles.We need model to add utility method so that we can easily get corresponding dimension data set column names according to given cube dimension keys.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Structure.java
setIntrinsicProperty( prop.getName( ), value );
	}
	/**
	 * Updates back reference for element reference value.
	 * 
	 * @param prop
	 *            the property
	 * @param value
	 *            value of the property
	 */
	protected void updateReference( PropertyDefn prop, Object value )
	{
		if ( value instanceof ElementRefValue
				&& prop.getTypeCode( ) == IPropertyType.ELEMENT_REF_TYPE )
		{
			ElementRefValue oldRef = (ElementRefValue) getLocalProperty( null,
					prop.getName( ) );
			doUpdateReference( oldRef, (ElementRefValue) value, prop );
		}
	}
	/**
	 * Implements to cache a back-pointer from a referenced element. This
	 * element has an element reference property that can point to another
	 * "referencable" element. To maintain semantic consistency, the referenced
	 * element maintains a list of "clients" that identifies the elements that
	 * refer to it. The client list is used when the target element changes
	 * names or is deleted. In these cases, the change automatically updates the
	 * clients as well.
	 * <p>
	 * References can be in two states: resovled and unresolved. An unresolved