Class: SPARQL::Algebra::Operator::Create

Inherits:
Operator
  • Object
show all
Includes:
Update
Defined in:
lib/sparql/algebra/operator/create.rb

Overview

The SPARQL UPDATE create operator.

This operation creates a graph in the Graph Store

This is a no-op for RDF.rb implementations, unless the graph exists

[34] Create ::= 'CREATE' 'SILENT'? GraphRef

Examples:

SPARQL Grammar

CREATE SILENT GRAPH <http://example.org/g1>

SSE

(update (create silent <http://example.org/g1>))

See Also:

Constant Summary collapse

NAME = 
[:create]

Instance Method Summary collapse

Methods included from Update

#empty?, #graph_name=, #unshift, #variables

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/create.rb', line 39

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

  iri = operands.first
  raise ArgumentError, "clear expected a single IRI" if operands.length != 1 || !iri.is_a?(RDF::URI)
  if queryable.has_graph?(iri)
    raise IOError, "create operation graph #{iri.to_ntriples} exists" unless silent
  end
  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/create.rb', line 57

def to_sparql(**options)
  silent = operands.first == :silent
  str = "CREATE "
  str << "SILENT " if operands.first == :silent
  str << "GRAPH " if operands.last.is_a?(RDF::URI)
  str << operands.last.to_sparql(**options)
end