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Bound and Unbound References

 

The objects in the system (both composite objects and individual information components) are actually structures of versions of the object as they have existed at various times. A reference to an object can thus be either a reference to a particular version (a bound reference) or an open reference (unbound) which is resolved at the point that the reference is used.   It is resolved currently to be the latest version in the temporal history although in later versions we may have a more complex resolution which also uses the development history. The use of unbound or open references ensures that one always gets the latest version of a component in a composite object. That is, if you have an unbound reference to a `person object' containing information about a person, you'll always get the latest information even as the components (telephone number, address, office, employer) change.

The use of bound references   ensures that one will always get a particular version of the object, regardless of whether it changes in the future. This can be useful for representing such things as printouts, where one wishes to match against an external existence.



Martin Sjolin
Mon May 29 19:53:45 MET DST 1995