The Zthes context-set for CQL

9th March 2006

CQL is the Contextual Query Language, a new (November 2002) query language intended to be both human-readable/writable and expressive. It's the query language of the SRU protocol (Search-Retrieve by URL). See the CQL tutorial for more information.

This page defines the Zthes context-set for CQL, containing indexes used to specify how to search in Zthes databases. The Zthes context-set is broadly equivalent to the Zthes-1 attribute set.

The Zthes context-set's conventional prefix is ``zthes'', so that queries using this context-set can typically be expressed as zthes.index=term.

Its unique identifier (used in certain contexts to unambiguously refer to this context-set, since the conventional ``zthes'' prefix is only a convention) is http://zthes.z3950.org/cql/version-number, for example, http://zthes.z3950.org/cql/1.0.1 for version 1.0.1 of the context-set.

The current version of the the Zthes CQL context set is version 1.0.1. Otherwise, in chronological order, we have:

(The numbering is idiosyncratic: for some reason, when the Zthes context set was first introduced for use in the Zthes SRU profile, it was given version number 1.0 rather than the 0.5 that it should have been allocated, to match the profile. As a result, the new version of the context set, which goes with the new version 1.0 of the profile, cannot be version 1.0; therefore a third facet is used to keep the context set's version number as close as possible to that of the SRU profile that uses it.)