NAME

       Attean::Plan - Representation of SPARQL query plan operators

VERSION

       This document describes Attean::Plan version 0.033

SYNOPSIS

         use v5.14;
         use Attean;

DESCRIPTION

       This is a utility package that defines all the Attean query plan classes in the
       Attean::Plan namespace:

       •   Attean::Plan::Quad

           Evaluates a quad pattern against the model.

       •   Attean::Plan::NestedLoopJoin

           Evaluates a join (natural-, anti-, or left-) using a nested loop.

       •   Attean::Plan::HashJoin

           Evaluates a join (natural-, anti-, or left-) using a hash join.

       •   Attean::Plan::Construct

       •   Attean::Plan::Describe

       •   Attean::Plan::EBVFilter

           Filters results from a sub-plan based on the effective boolean value of a named
           variable binding.

       •   Attean::Plan::Merge

           Evaluates a set of sub-plans, returning the merged union of results, preserving
           ordering.

       •   Attean::Plan::Union

           Evaluates a set of sub-plans, returning the union of results.

       •   Attean::Plan::Extend

           Evaluates a sub-plan, and extends each result by evaluating a set of expressions,
           binding the produced values to new variables.

       •   Attean::Plan::HashDistinct

           Evaluates a sub-plan, and returns distinct results by checking a persistent hash of
           already-seen results.

       •   Attean::Plan::Unique

           Evaluates an already-ordered sub-plan, and returns distinct results by filtering out
           sequential duplicates.

       •   Attean::Plan::Slice

           Evaluates a sub-plan, and returns the results after optionally skipping some number of
           results ("offset") and limiting the total number of returned results ("limit").

       •   Attean::Plan::Project

           Evaluates a sub-plan and returns projected results by only keeping a fixed-set of
           variable bindings in each result.

       •   Attean::Plan::OrderBy

           Evaluates a sub-plan and returns the results after fully materializing and sorting is
           applied.

       •   Attean::Plan::Service

           Evaluates a SPARQL query against a remote endpoint.

       •   Attean::Plan::Table

           Returns a constant set of results.

       •   Attean::Plan::Iterator

           Returns a constant set of results.

           Be aware that if the iterator being wrapped is not repeatable (consuming the
           Attean::API::RepeatableIterator role), then this plan may only be evaluated once.

           A size estimate may be given if it is available. If the iterator is an
           Attean::ListIterator, the size of that iterator will be used.

       •   Attean::Plan::ALPPath

       •   Attean::Plan::Exists

           Returns an iterator containing a single boolean term indicating whether any results
           were produced by evaluating the sub-plan.

       •   Attean::Plan::Aggregate

BUGS

       Please report any bugs or feature requests to through the GitHub web interface at
       <https://github.com/kasei/attean/issues>.

SEE ALSO

AUTHOR

       Gregory Todd Williams  "<gwilliams@cpan.org>"

COPYRIGHT

       Copyright (c) 2014--2022 Gregory Todd Williams.  This program is free software; you can
       redistribute it and/or modify it under the same terms as Perl itself.