Class: SPARQL::Algebra::Operator::Modify

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

Overview

The SPARQL UPDATE ‘modify` operator.

Wraps delete/insert

If ‘options` contains any of the Protocol attributes, it is treated as if there is a USING or USING NAMED clause inserted.

  • ‘using-graph-uri`

  • ‘using-named-graph-uri`

41

Modify ::= ( ‘WITH’ iri )? ( DeleteClause InsertClause? | InsertClause ) UsingClause* ‘WHERE’ GroupGraphPattern

Examples:

SPARQL Grammar

PREFIX     : <http://example.org/> 
PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
DELETE  { ?a foaf:knows ?b }
INSERT { ?b foaf:knows ?a }
WHERE { ?a foaf:knows ?b }

SSE

(prefix ((: <http://example.org/>)
         (foaf: <http://xmlns.com/foaf/0.1/>))
 (update
  (modify
   (bgp (triple ?a foaf:knows ?b))
   (delete ((triple ?a foaf:knows ?b)))
   (insert ((triple ?b foaf:knows ?a)))) ))

See Also:

  • XXX

Constant Summary collapse

NAME = 
[:modify]

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, #constant?, #deep_dup, #each_descendant, #eql?, #evaluatable?, evaluate, #executable?, #first_ancestor, for, #initialize, #inspect, #mergable?, #ndvars, #node?, #operand, #optimize, #optimize!, #parent, #parent=, #prefixes, prefixes, prefixes=, #rewrite, 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.

Execute the first operand to get solutions, and apply those solutions to the subsequent operators.

If ‘options` contains any of the Protocol attributes, any `using` clause is removed and a new `using` clause is added with entries taken from the `using-graph-uri` and `using-named-graph-uri`.

It is an error to supply the using-graph-uri or using-named-graph-uri parameters when using this protocol to convey a SPARQL 1.1 Update request that contains an operation that uses the USING, USING NAMED, or WITH clause.

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/modify.rb', line 58

def execute(queryable, **options)
  debug(options) {"Modify"}
  query = operands.shift

  if %i(using-graph-uri using-named-graph-uri).any? {|k| options.key?(k)}
    raise ArgumentError,
      "query contains USING/WITH clause, which is incompatible with using-graph-uri or using-named-graph-uri query parameters" if
      query.is_a?(Operator::Using) || query.is_a?(Operator::With)

    debug("=> Insert USING clause", options)
    defaults = Array(options.delete(:'using-graph-uri')).map {|uri| RDF::URI(uri)}
    named = Array(options.delete(:'using-named-graph-uri')).map {|uri| [:named, RDF::URI(uri)]}
    
    query = Operator::Using.new((defaults + named), query, **options)
  end

  queryable.query(query, **options.merge(depth: options[:depth].to_i + 1)) do |solution|
    debug(options) {"(solution)=>#{solution.inspect}"}

    # Execute each operand with queryable and solution
    operands.each do |op|
      op.execute(queryable, solutions: solution, **options.merge(depth: options[:depth].to_i + 1))
    end
  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/modify.rb', line 90

def to_sparql(**options)
  if operands.first.is_a?(With)
    operands.first.to_sparql(**options)
  else
    # The content of the WHERE clause, may be USING
    content = operands.first.to_sparql(top_level: false, **options)

    # DELETE | INSERT | DELETE INSERT
    str = operands[1..-1].to_sparql(top_level: false, delimiter: "\n", **options) + "\n"

    # Append the WHERE or USING clause
    str << if operands.first.is_a?(Using)
      content
    else
      Operator.to_sparql(content, project: nil, **options)
    end
  end
end