Re: Hierarchical databases and semistructured data
Date: Thu, 21 Feb 2002 10:53:07 +0100
Message-ID: <3c74c324$1_at_news.uia.ac.be>
"Morten" <morten_at_kikobu.com> wrote in message
news:3C73F433.2090001_at_kikobu.com...
>
> Incidentally, I have the book and Buneman's semistructured data article.
> Their models for semistructured data bring up another question.
> Do you happen to know if this model has changed - or if there are just
> several ways of expressing the same model.
The latter. Peter Buneman actually discusses several possiblities in his
tutorial which are more or less equivalent. The version where only edges are
labeled is mathematically more elegant, but the one with the labeled leaves
is more common.
> by the figure in the article, and the figure on page 33 in the book,
> basically the leaves of the tree in the book have value, whereas they
> are "void" in the article, but have a label of a "type" (rather than a
> symbol I assume)