Re: [SML] Whether to support Attribute or not?
> > If you have to "dig" into the contents to figure > > out which "processing pipeline" the content is > > placed on then you have effectively elminated > > all hope of sequential processing. Thus, you > > need random access to the information stream. > > And hence, "large" memory requiremens, thus > > undermining the apparant "simplicity" of SML. > > > > Well, I don't agree with you on this point. I have been working > on a streaming query processor for XML for some time, and the > problem is just not there. Why is it a problem going into the > element one or two levels deep? Besides the chances that you will > encode all the information relevant to the query processor into > attributes is very small. Consider the example above with the > local schools: what if I want to select all homes that have > some specific school in their neighborhood? This information > cannot be encoded in the attributes, since its nested. But I > can still stream such queries, all I have to do is descend one > level into each element and the find the school that satisfies > the condition. This is exactly the point. Attributes kludge allows easier processing when the hierarchy has only one level and *only* in this situation. <foo><att>Attr</att></foo> - when processing it with SAX no easy way to implement the 'look-forward' rule of kind 'If foo has a child ( property ) Attr' <foo att="Attr"></foo> - when processing it with SAX it is easy to implement the 'look-forward' rule of kind 'If foo has a child ( property ) Attr' As any other kludge, attributes kludge allows you to process some percent of more easily than without that klugde. Like any other kludge even it gives you something, it costs something. I think what it gives is not worth what it costs. Your mileage may vary, but for sure there is no logical arguments here. " Does this kludge simplyfy some things? - Yes it does. Does it makes some other things harder? - Yes it does." What is more important? We can only guess, because if some developer is concentrated only on processing some simple XML documents with SAX - for sure Attributes kludge is very convinient. Developer who tries to invent the new XQL ( with updates ;-) may have another point of view on this subject. I don't know who is closer to the 'truth' ;-) Not talking about the changes one should make to the SAX handler ( XT stylesheet e t.c. ) in the situation when something designed to be attribute turns into element. Rgds.Paul. xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format