Class: SPARQL::Algebra::Operator::Drop

Inherits:
SPARQL::Algebra::Operator show all
Includes:
Update
Defined in:
vendor/bundler/ruby/2.5.0/bundler/gems/sparql-b66c70fb77a0/lib/sparql/algebra/operator/drop.rb

Overview

The SPARQL UPDATE drop operator.

The DROP operation removes the specified graph(s) from the Graph Store

Equivalent to clear in this implementation

Examples:

(drop default)

See Also:

Constant Summary collapse

NAME =
[:drop]

Constants inherited from SPARQL::Algebra::Operator

ARITY, IsURI, URI

Instance Attribute Summary

Attributes inherited from SPARQL::Algebra::Operator

#operands

Instance Method Summary collapse

Methods included from Update

#graph_name=, #unshift, #variables

Methods inherited from SPARQL::Algebra::Operator

#aggregate?, arity, #base_uri, base_uri, base_uri=, #boolean, #constant?, #each_descendant, #eql?, #evaluatable?, evaluate, #executable?, #first_ancestor, for, #initialize, #inspect, #ndvars, #node?, #operand, #optimize, #parent, #parent=, prefixes, #prefixes, prefixes=, #rewrite, #to_binary, #to_sxp, #to_sxp_bin, #validate!, #variable?, #vars

Methods included from Expression

cast, #constant?, #evaluate, extension, extensions, for, #invalid?, new, #node?, open, #optimize, parse, register_extension, #to_sxp_bin, #valid?, #validate!, #variable?

Constructor Details

This class inherits a constructor from SPARQL::Algebra::Operator

Instance Method Details

#execute(queryable, options = {}) ⇒ RDF::Queryable

Executes this upate on the given writable graph or repository.

Parameters:

  • queryable (RDF::Queryable)

    the graph or repository to write

  • options (Hash{Symbol => Object}) (defaults to: {})

    any additional keyword options

Options Hash (options):

  • debug (Boolean)

    Query execution debugging

Returns:

Raises:

  • (IOError)

    If from does not exist, unless the silent operator is present

See Also:



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# File 'vendor/bundler/ruby/2.5.0/bundler/gems/sparql-b66c70fb77a0/lib/sparql/algebra/operator/drop.rb', line 34

def execute(queryable, options = {})
  debug(options) {"Drop"}
  silent = operands.first == :silent
  silent = operands.first == :silent
  operands.shift if silent

  raise ArgumentError, "drop expected operand to be 'default', 'named', 'all', or an IRI" unless operands.length == 1
  case operands.last
  when :default
    queryable.each_graph do |g|
      g.clear! unless g.graph_name
    end
  when :named
    queryable.each_graph do |g|
      g.clear! if g.graph_name
    end
  when :all
    queryable.clear!
  when RDF::URI
    if g = queryable.each_graph.detect {|c| c.graph_name == operands.last}
      g.clear!
    else
      raise IOError, "drop operation graph does not exist" unless silent
    end
  else
    raise ArgumentError, "drop expected operand to be 'default', 'named', 'all', or an IRI" 
  end

  queryable
end