4. Server Side CQL to PQF Query Translation

Using the <cql2rpn>l2rpn.txt</cql2rpn> YAZ Frontend Virtual Hosts option, one can configure the YAZ Frontend CQL-to-PQF converter, specifying the interpretation of various CQL indexes, relations, etc. in terms of Type-1 query attributes.

For example, using server-side CQL-to-PQF conversion, one might query a zebra server like this:

     yaz-client localhost:9999
     Z> querytype cql
     Z> find text=(plant and soil)

and - if properly configured - even static relevance ranking can be performed using CQL query syntax:

     Z> find text = /relevant (plant and soil)

By the way, the same configuration can be used to search using client-side CQL-to-PQF conversion: (the only difference is querytype cql2rpn instead of querytype cql, and the call specifying a local conversion file)

     yaz-client -q local/cql2pqf.txt localhost:9999
     Z> querytype cql2rpn
     Z> find text=(plant and soil)

Exhaustive information can be found in the Section CQL to RPN conversion in the YAZ manual.