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I think I have to use some of our own terminology, probably not very well known to lot of people, though I think it can be guessed. First terminology is a regular tree grammar = an XML Schema. I thought about this a little bit after we discussed about ambiguities in regular tree grammars. This is very tentative -- I think key constraints are specified in schema by saying something like -- for all values of Book type, the key is so and so -- have to verify this with XML Schema. But when we have ambiguities, we do not know exactly what are Book types. I think we should get around this a little bit -- there could be multiple solutions -- first check whether we can ensure that when we have to specify key constraints (I think results of document processing do not need to specify key constraints), therefore I tentatively believe that we need key constraints only for the initial data modeling part, then there can possibly be multiple solutions -- either ensure that the DB designer can specify only unambiguous grammars (is this solution good enough?) or warn the designer, or set a rule for handling ambiguities. Other solutions also could be possible. This needs some more concrete work, and I am very thankful for your input on ambiguities in regular tree grammars -- I think it is *very* useful. I think what we need for handling key constraints easily is non-ambiguous regular tree grammars, but XML Schema is a *very* small subset of non-ambiguous regular tree grammars. <warning>speaking for himself only<warning> regards - murali. On Tue, 17 Apr 2001, Kohsuke KAWAGUCHI wrote: > > > Tentatively, deterministic content models are easier for specifying key > > constraints, but I think document processing (such as XSLT or Query) gets > > I really appreciate if you would teach me how key constraint enforcement > gets easier in deterministic content model. > > > ---- > Kohsuke KAWAGUCHI > Phone: 650-786-0721 > >
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