NAME

       Attean::API::Plan - Query plan

VERSION

       This document describes Attean::API::Plan version 0.019

DESCRIPTION

       The Attean::API::Plan role defines a common API for all query plans.

ATTRIBUTES

       "cost"
       "distinct"
       "item_type"
       "in_scope_variables"
       "ordered"

REQUIRED METHODS

       The following methods are required by the Attean::API::Plan role:

       "impl( $model )"
           Returns a code reference that when called (without arguments), returns an
           Attean::API::Iterator object.

METHODS

       "has_cost"
       "as_string"
           Returns a tree-structured string representation of this plan, including children.

       "evaluate( $model )"
           Evaluates this plan and returns the resulting iterator.

       "in_scope_variables_union( @plans )"
           Returns the set union of "in_scope_variables" of the given plan objects.

       "subplans_of_type_are_variable_connected( $type )"
           Returns true if the subpatterns of the given $type are all connected through their
           "in_scope_variables", false otherwise (implying a cartesian product if the connecting
           plans perform some form of join.

       "children_are_variable_connected( $type )"
           Returns true if the children of this plan are all connected through their
           "in_scope_variables", false otherwise (implying a cartesian product if this plan
           performs some form of join.

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--2018 Gregory Todd Williams.  This program is free software; you can
       redistribute it and/or modify it under the same terms as Perl itself.