window queries in mxquery 0.6

2009-08-12
2013-06-05
  • Michael Menzel
    Michael Menzel
    2009-08-12

    Hi,

    I tried the 0.4.x version before and window queries ran as expected and according to the "Extending XQuery with Window Functions" paper.

    What has changed in 0.6? Using the syntax proposed in current XQuery 1.1 draft doesn't work either.
    Parser throws an error on "forseq " as first word of flowr and equal kind of error on "for tumbling window ...". on forseq he calls "forseq" to be the reason and on "for tumbling window" the parser expects a varname ("$var") instead of "tumbling window".

    How's the syntax?

    regards
    Michael

     
    • Hi Michael,

      the syntax is correct (in both cases).

      What has changed, however, is the way how MXQuery treats the different languages/extensions.

      0.4 and before would always consider all extensions when compiling a query.
      Since the Scripting 1.0 (especially extended update compatibility) changes to semantics of expressions so that they would violate the "previous" standard (Update Facility), we now explicitly enable/disable support for particular languages/extensions. The default is to consider XQuery 1.0 only, other languages/extensions need to be enabled.

      On the command line, please use the "XQuery language features" parameters - see http://mxquery.org/?page_id=27

      If you use the Java API, please set the appropriate settings in the ch.ethz.mxquery.contextConfig.CompilerOption class - it is now a parameter of the compile methods

      For XQJ, we are currently preparing an extensions that would also allow passing these parameter.

      Hope that helps,
      Peter

       
      • Michael Menzel
        Michael Menzel
        2009-08-13

        Thanks Peter,

        That makes sense! Haven't mentioned you changed it into an option. Didn't give the CompilerOptions enough attention yet.

        It's working now.

        I opened another thread about "contniuous query". Hope you can answer that one too.

        Regards
        Michael