- From: Judith Slein <slein@wrc.xerox.com>
- Date: Fri, 17 Apr 1998 13:04:51 PDT
- 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 E-Mail: slein@wrc.xerox.com Internal Phone: 8*222-5169 Fax: (716) 422-2938 MailStop: 105-50C Web Site: http://www.nde.wrc.xerox.com/users/Slein/slein.htm
Received on Friday, 17 April 1998 17:50:10 UTC