RDF::Trine::Pattern - Class for basic graph patterns

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

       Kjetil Kjernsmo "<kjetilk@cpan.org>"

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

       Copyright (c) 2006-2012 Gregory Todd Williams. This program is free software;  you  can  redistribute  it
       and/or modify it under the same terms as Perl itself.

perl v5.38.2                                       2024-01-13                           RDF::Trine::Pattern(3pm)

       "new ( @triples )"
           Returns a new BasicGraphPattern structure.

       "construct_args"
           Returns  a  list  of  arguments that, passed to this class' constructor, will produce a clone of this
           algebra pattern.

       "triples"
           Returns a list of triples belonging to this BGP.

       "type"
       "sse"
           Returns the SSE string for this algebra expression.

       "referenced_variables"
           Returns a list of the variable names used in this algebra expression.

       "definite_variables"
           Returns a list of the variable names that will be bound after evaluating this algebra expression.

       "clone"
       "bind_variables ( \%bound )"
           Returns a new pattern with variables named in %bound replaced by their corresponding bound values.

       "subsumes ( $statement )"
           Returns true if the pattern will subsume the $statement when matched against a triple store.

       "merge_patterns ( @patterns )"
           Given an array of patterns, this will merge them into one.

       "sort_for_join_variables"
           Returns a new pattern object with the subpatterns of the referrant sorted based  on  heuristics  that
           ensure firstly that patterns can be joined on the same variable and secondly on the usual selectivity
           (i.e.  how  quickly  the  engine  can drill down to the answer) of triple patterns. Calls "subgroup",
           "sort_triples" and "merge_patterns" in that order.

       "subgroup"
           Splits the pattern object up in an array of pattern objects where the same triple patterns occur.  It
           will  group  on  common  variables,  so  that  triple  patterns  can be joined together is in a group
           together. It will also group triples that have no connection to other triples in  a  group.  It  will
           then  order  the  groups,  first by number triples with common variables, then by number of literals,
           then by the total number of terms that are not variables.

       "sort_triples"
           Will sort the triple patterns based on heuristics that looks at how many variables the patterns have,
           and where they occur, see REFERENCES for details. Returns a new sorted pattern object.

       RDF::Trine::Pattern - Class for basic graph patterns

       The  heuristics  to  order  triple  patterns  in  this  module  is  strongly  influenced by The ICS-FORTH
       Heuristics-based SPARQL Planner (HSP) <http://www.ics.forth.gr/isl/index_main.php?l=e&c=645>.

       This document describes RDF::Trine::Pattern version 1.019