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Re: Doc vs. Data

• To: xml-dev@l...
• Subject: Re: Doc vs. Data
• From: ari@c... (K. Ari Krupnikov)
• Date: 07 Jun 2003 04:13:31 -0700
• In-reply-to: <01ac01c32cc0$a6b52c20$4bc8a8c0@A...>
• References: <B885BEDCB3664E4AB1C72F1D85CB29F806484451@R...><01ac01c32cc0$a6b52c20$4bc8a8c0@A...>
• Sender: ari@l...
• User-agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2

"Rick Jelliffe" <ricko@a...> writes:

> From: "Dare Obasanjo" <dareo@m...>
> 
> > I do agree that mixed content is the  probably the most relevant 
> > differentiator between data-centric & document-centric uses of XML.
> 
> I think mixed content also entails some other things:
>   * a presumption that data and elements are ordered, 
>   * a presumption that tags delimit ranges within some larger text stream
>    rather than independent atoms of information.
> These presumptions then require some syntactic form for better
> representing information items that are not mutually ordered and do contain
> atoms rather than ranges: hence attribute syntax.

Not to contradict this observation, but I don't think XML attributes
are almost exclusively of value to docheads.

I find an excellent, language-level, round-trippable mapping between
XML attributes and relational ones. Note that the mapping to elements
is not nearly as good.

* Like SQL attributes, XML attributes are semantically unordered.
* SQL attribute names must be unique within a relation, XML attribute
  names must be unique in an element.
* SQL attributes can be NULLable; XML attributes can be #IMPLIED.
* Like SQL attributes, XML attributes have names and atomic values
  (SQL99 even has an (anti-1NF) array datatype to map to tokenized
  attributes).
* XML attributes on an element can be viewed as a relation named by
  that element and vice versa.

<PERSON NAME="K. Ari Krupnikov" EMAIL="ari@c..." READS="xml-dev"/>

INSERT INTO PERSON (NAME, EMAIL, READS)
        VALUES ("K. Ari Krupnikov", "ari@c...", "xml-dev")

Ari.

• Follow-Ups:
  • Re: Doc vs. Data
    • From: Norman Walsh <ndw@n...>

• References:
  • RE: Doc vs. Data
    • From: "Dare Obasanjo" <dareo@m...>
  • Re: Doc vs. Data
    • From: "Rick Jelliffe" <ricko@a...>

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