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RE: use of boolean literals

From: Judith Slein <slein@wrc.xerox.com>
Date: Fri, 17 Apr 1998 13:04:51 PDT
Message-Id: <>
To: "Babich, Alan" <ABabich@filenet.com>
Cc: "'Saveen Reddy (Exchange)'" <saveenr@Exchange.Microsoft.com>, www-webdav-dasl@w3.org
I think in the DAV world it does make sense to ask whether a property
exists on a given resource, where you are not testing for a null value.  A
DAV server may allow clients to define whatever properties they wish on any
resource, so that it may turn out every resource on the server has a
different set of properties.  

At 06:56 PM 4/16/98 PDT, Babich, Alan wrote:
>(1) Testing for the existence of a property is testing for null.
>In the context of an RDBMS, that means that the property
>is defined, but on the particular resource, it has no value.
>In contrast, if the property is not DEFINED anywhere, that is
>generally treated as a query syntax error.
>I have no objection to an operator that tests for whether
>a particular property has a value for the current resource
>under scan. In SQL, that would be expressed as
>"x IS NULL". Generally, the "IS NULL" operator returns
>TRUE or FALSE. However, is x is not defined anywhere,
>it should return UNKNOWN. Whether "IS NULL" should be in
>the required set of operators as opposed to merely
>being a well known operator is a subject for discussion.

Name:			Judith A. Slein
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Received on Friday, 17 April 1998 17:50:10 UTC

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