Class: SPARQL::Algebra::Operator::Load

Inherits:
SPARQL::Algebra::Operator show all
Includes:
Update
Defined in:
lib/sparql/algebra/operator/load.rb

Overview

The SPARQL UPDATE load operator.

The LOAD operation reads an RDF document from a IRI and inserts its triples into the specified graph in the Graph Store. The specified destination graph should be created if required; again, implementations providing an update service over a fixed set of graphs must return with failure for a request that would create a disallowed graph. If the destination graph already exists, then no data in that graph will be removed.

[31] Load ::= ‘LOAD’ ‘SILENT’? iri ( ‘INTO’ GraphRef )?

Examples:

SPARQL Grammar

LOAD <http://example.org/remote> INTO GRAPH <http://example.org/g> ;

SSE

(update (load <http://example.org/remote> <http://example.org/g>))

See Also:

Constant Summary collapse

NAME = 
[:load]

Constants inherited from SPARQL::Algebra::Operator

ARITY, IsURI, URI

Constants included from Expression

Expression::PATTERN_PARENTS

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

Methods included from Expression

cast, #constant?, #evaluate, extension, extension?, extensions, for, #invalid?, new, #node?, open, #optimize, #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}) —

    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 'lib/sparql/algebra/operator/load.rb', line 38

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

  raise ArgumentError, "load expected one or two operands, got #{operands.length}" unless [1,2].include?(operands.length)

  location, name = operands
  queryable.load(location, graph_name: name)
rescue IOError, Errno::ENOENT
  raise unless silent
ensure
  queryable
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/load.rb', line 58

def to_sparql(**options)
  silent = operands.first == :silent
  ops = silent ? operands[1..-1] : operands
  location, name = ops

  str = "LOAD "
  str << "SILENT " if silent
  str << location.to_sparql(**options)
  str << " INTO GRAPH " + name.to_sparql(**options) if name
  str
end