Integrity in the Hands of the Client

Tim Bray tbray at
Fri Nov 21 17:01:52 GMT 1997

At 10:56 AM 21/11/97 -0500, Joe Lapp wrote:
>In this posting I'm going to be a little bold and propose that both
>the XML and DOM specifications are flawed.  

Mr. Lapp has discovered one of the well-known shortcomings of SGML,
inherited by XML; namely, the typing and constraint mechanisms supplied
by DTDs are well-known to be insufficiently rich to allow their use
for purposes which we have come to expect of database schemas.  

More obviously, if, in Mr. Lapp's example, I wanted to give prices
for the books, I might want to be able to say that this has to be 
a number, with 2 digits right of the decimal point.  SGML doesn't
help you here either.

Yes; we need a new and richer form of schema.  No boldness is
required. -Tim

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