SRU/OASIS: Paramerized Query - draft message

["Ray Denenberg, Library of Congress" <rden@loc.gov>]

Draft message:

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There is a desire among some committee members to incorporate support for
Parameterized Query.

In Parameterized Query there is a complete query pre-configured on the
server complete with all supported predicates, and parameter variables.
Clients invoke the query by  id and supply a subset of supported parameters.
(The server prunes the query to remove predicate for which parameters  were
not supplied.)

A typical PQ request might look like:

                      http ://example.com/search?queryId=123&name=japan

Which isn't consistent with SRU/CQL syntax.

Alternatively a CQL query could be constructed so the request would look
like

             http ://example.com/search?query=queryId=123&20and&20name=japan

That is, an index, 'queryId',  would be defined,  and there would be rules
associated with this index, for example, when a query uses this index,  the
remainder of the query must be limited to boolean ANDs and predicates where
the relation is always '=" and the index corresponds to a parameter defined
by the stored query.

There has been debate within the committee. Some are comfortable with
representing PQ as just another CQL query (with the restrictions stated
above) while other members feel that these  special case semantics and
constraints are indicative of an unstable design for supporting
parameterized queries, and would like to see PQ singled out as a special
mode of operation.

SRU implementor feedback is solicited on this issue.