Grandi) wrote:Why not? SGML is powerful enough: I can simply use links to represent any
> The formats you allude to above are defective not because they are not
> ``rich'' enough, but because they are based on weak data models. Now,
> designing a proper data model is not an easy thing; using a document
> structure notation (based on somewhat context free grammars) as a data
> modeling notation does not quite work.
arbitrary graph, either within a document, or between documents.
> Just to illustrate some issues, consider the simple idea that if youIt seems to me this is a problem arising from the need for documents to be
> know ten people that all work for the same company at the same site, you
> don't want to replicate the common data many times; also, if some
> people, e.g. consultants, work at several companies, or some employee
> work at several sites for the same company, you also want to avoid
> duplicating data about that as well.
self-contained for interchange, but 'relational' (i.e. common data
factored out) when stored in a database. This means no matter what
data-formats I use, some kind of processing needs to be done when
accepting a new entry into the database.
Therefore, I claim:
1. SGML markup can represent information, not just document structure. I
2. It's possible to create an SGML DTD powerful enough to properly
3. It's possible to design a contact-manager to recognise already existing
> You end up with a many-to-many relationship between people andIsn't a graph structure the same thing as a many-to-many relationship?
> companies, and perhaps a one-to-many between companies and sites. These
> cannot be expressed easily with anything but a full featured data model,
> (relational, DBTG CODASYL, E-R, and a few others) and not even with
> HyTyme (SGML DTDs describe hierarchical structures; HyTime describes
> graph structures, indirectly).
> What one can do in SGML is not quite to "describe the informationI believe SMDL can represent information directly, and I believe there are
> properly and clearly", but to describe, properly and clearly, _reports_
> containing that information. Then the very useful and important theme of
> using SGML DTDs to describe the structure of database output comes
a number of other existing applications of SGML that involve representing
semantic information rather than reports of that information.
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