itana@minster.york.ac.uk (03/19/91)
Does anyone know if it is possible to specify integrity constraints in ONTOS? I would also be grateful if someone could suggest good references on how integrity has been treated in Object Oriented Databases. thanks, Itana ------------------------------------------------------------------------ Itana M S Gimenes | JANET itana@uk.ac.york.minster The University of York | BITNET Dept of Computer Science | INTERNET Heslington YORK Y01 5DD | Fax No: +44 (0904) 43 2767 ENGLAND - UK | PHONE +44 (0904) 43 2788 ------------------------------------------------------------------------
davidm@uunet.UU.NET (David S. Masterson) (03/22/91)
>>>>> On 19 Mar 91 14:03:15 GMT, itana@minster.york.ac.uk said:
Itana> Does anyone know if it is possible to specify integrity
Itana> constraints in ONTOS?
Itana> I would also be grateful if someone could suggest good
Itana> references on how integrity has been treated in Object
Itana> Oriented Databases.
That reminds me that I wanted to ask a question about how constraints are
supported in OODBs. If I understand the precepts of object-orientation (and I
could be way off), objects support constraints as a behaviour in their
definition. While doing their processing, they check that a behavioral
constraint is not violated by their processing. However, this seems to be
related to the definition of the object itself whereas constraints may be
based on the definition of the relationships of multiple objects. For
instance, a constraint on object A might be that it cannot exist unless object
B also exists (referential integrity). If an attempt to delete object B is
made, though, what in the definition of the behaviour of B would prevent the
operation until corresponding As have been deleted? Must both objects A and B
be modified to account for the referential integrity constraint?
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