DOM SAX? which one and why? and where is the overview NOTE to all this XML?

[Trevor Croll]

Having looked hard at this issue I will be using a DOM parser.

I will be using DTD only to provide Entities and the properties of the
fields of those entities

I will be using an XML document to then provide a document data structure
where the "entities are linked together to provide a structure to the
document.

I have not yet worked out how or which NOTE will bets help this.

Then I will use some sort of XSCHEMA where the structure is enhanced so data
can be added to it. I do not know which sort this is.

I see that I have to have three levels before I cab get data into the
document.

The world as I see it is made up of entities, entities together produce an
item.(DTD)  ( ie. Person details plus his address details etc make up the
item Person) ITEM PERSON = entity person + entity address + entity phone +
entity email etc..(XML) like XML-DATA to link entities into items.

Data entry requires a schema that understands this
HTML requires a verified XSL that takes the data and displayes it as a HTML
screen.

The overview of XML and the uses of the various parts is very difficult to
find. It would be nice if there was somewhere some note on how the various
standards could be used and relate to each other, ONE such over view is
provided by ATL at www.atl-systems.co.jp and this is only for that project.





----- Original Message -----
From: Chris Harris <christopher.harris at reuters.com>
To: <xml-dev at ic.ac.uk>
Sent: Wednesday, July 21, 1999 10:05 PM


> I came up against this issue in some work I've been doing recently on Java
> XML parser performance, would be interested in comments etc.
>
> There are two main APIs for applications that process XML documents - DOM
> (Document Object Model) and SAX (Simple API to XML). DOM involves
> constructing a tree of Nodes from the XML document, and then using a
simple
> API to walk the tree and extract information from it. SAX is an event
based
> API designed to fire user-written code as elements etc. are encountered in
> the parsing of the document. SAX is very useful when the document may be
> too large to fit into memory.
>
> Validation of a document means ensuring that the document conforms
entirely
> to the DTD for that document. In practice, this means that the entire
> document has to fit into memory since validation cannot be completed until
> the whole document has been parsed. This fits well with the DOM model, but
> is somewhat in opposition to the SAX philosophy where most of the action
is
> done during the document parse.
>
> This is not to say that you cannot use a validating parser with SAX, in
> fact all the major parsers provide such capability. It's quite possible to
> execute all your business logic during the SAX parse, and then throw it
> away if the parse fails at the end of the document.
>
> My question is really, for those of you who are writing XML processors
> (i.e. applications that use XML), what mode(s) do you use, and do you find
> the need for a validating SAX parser?
>
> It's interesting to note that, in IBM's xml4j parser, the SAX parser is by
> default non-validating, and the DOM parser is by default validating.
>
> c
>
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