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RE: datatyping is not needed

From: Jim Davis <jdavis@parc.xerox.com>
Date: Tue, 7 Jul 1998 13:08:55 PDT
Message-Id: <3.0.3.32.19980707130855.007fd100@mailback.parc.xerox.com>
To: www-webdav-dasl@w3.org
At 10:24 PM 7/6/98 PDT, Babich, Alan wrote:
 
>As regards to the conclusion, even
>if you buy the premise, the conclusion doesn't follow: (1) So I 
>couldn't afford a Ferrari Testarosa, so a Corvette 
>is no good at all, and so I walk? 

Well, I meant to make a claim more analogous to this one:
 1) Some drivers want to travel at 100 mph
 2) DASL has to choose between walking and a bicycle
 --> DASL should walk, because those who desire speed will buy a car, and
wouldn't use the bicycle anyway.

The really fancy UI is like the car.  It needs a very rich and complex set
of metadata.  DASL can provide, at most, the base datatype, which is like
the bicycle, but nothing else.  (Even the XML Data drafts don't go beyond,
at most, some simple ranges limits.  Still more like a Geo Metro.)  Since
this won't satisfy the fast car people, and the pedestrians don't care at
all, we can skip it altogether and save effort.

Smart UIs will use out of band information to get this metadata, including,
but not limited to, private agreements among implementors.  They can still
transmit the query using DASL.

Someday we may be able to put this kind of smarts into DASL.  Not this
version.

> However, for the sake of interoperability,
>DASL must state that the datatype of the literal must be compatible
>with the datatype of the property and give all the details.

I am not sure what details you are asking for.  Would this require DASL to
state the base datatypes for every RDBMS, OODB, and DMS known to humanity?

Please recall also that DASL might well be used to query non-traditional
databases, e.g. job management systems, airline reservation systems, coffee
machines.

Let me try to stake out two other positions that lie between the two we've
argued for.  perhaps one will be an acceptable compromise

1) The syntax of properties in the Query Schema Discovery will allow for an
optional datatype field (attribute or XML element, I don't care much).  The
datatypes will be a subset of those defined in XML Data sufficient for
WebDAV properties.  The only use of datatyping in DASL will be in schema
discovery, not in query terms.

2) No datatyping in DASL 1.0, but we promise (as a WG) that DASL 2.0 will
incorporate XML Data in its full power and expressiveness as soon as XML
Data stabilizes (provided it does, and provided there's not a better car
available then.)

Position 1 is sort of like the bicycle.  It costs us very little and
settling the point would allow us to move on.  Position 2 is maybe more
like being promised a car when one graduates high school.

Does either of these appeal to you?
Received on Tuesday, 7 July 1998 17:41:39 GMT

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