Class Ask

Represents the Ask step of Query Evaluation.
Inheritance
System.Object
Ask
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: VDS.RDF.Query.Algebra
Assembly: dotNetRDF.dll
Syntax
public class Ask : IUnaryOperator, ISparqlAlgebra
Remarks
Used only for ASK queries. Turns the final Multiset into either an IdentityMultiset if the ASK succeeds or a NullMultiset if the ASK fails.

Constructors

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Ask(ISparqlAlgebra)

Creates a new ASK.
Declaration
public Ask(ISparqlAlgebra pattern)
Parameters
Type Name Description
ISparqlAlgebra pattern Inner Pattern.

Properties

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FixedVariables

Gets the enumeration of fixed variables in the algebra i.e. variables that are guaranteed to have a bound value.
Declaration
public IEnumerable<string> FixedVariables { get; }
Property Value
Type Description
System.Collections.Generic.IEnumerable<System.String>
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FloatingVariables

Gets the enumeration of floating variables in the algebra i.e. variables that are not guaranteed to have a bound value.
Declaration
public IEnumerable<string> FloatingVariables { get; }
Property Value
Type Description
System.Collections.Generic.IEnumerable<System.String>
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InnerAlgebra

Gets the Inner Algebra.
Declaration
public ISparqlAlgebra InnerAlgebra { get; }
Property Value
Type Description
ISparqlAlgebra
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Variables

Gets the Variables used in the Algebra.
Declaration
public IEnumerable<string> Variables { get; }
Property Value
Type Description
System.Collections.Generic.IEnumerable<System.String>

Methods

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Evaluate(SparqlEvaluationContext)

Evaluates the ASK by turning the Results of evaluating the Inner Pattern to either an Identity/Null Multiset depending on whether there were any Results.
Declaration
public BaseMultiset Evaluate(SparqlEvaluationContext context)
Parameters
Type Name Description
SparqlEvaluationContext context Evaluation Context.
Returns
Type Description
BaseMultiset
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ToGraphPattern()

Throws an exception since an Ask() cannot be converted to a Graph Pattern.
Declaration
public GraphPattern ToGraphPattern()
Returns
Type Description
GraphPattern
Exceptions
Type Condition
System.NotSupportedException Thrown since an Ask() cannot be converted to a Graph Pattern.
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ToQuery()

Converts the Algebra back to a SPARQL Query.
Declaration
public SparqlQuery ToQuery()
Returns
Type Description
SparqlQuery
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ToString()

Gets the String representation of the Ask.
Declaration
public override string ToString()
Returns
Type Description
System.String
Overrides
System.Object.ToString()
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Transform(IAlgebraOptimiser)

Transforms the Inner Algebra using the given Optimiser.
Declaration
public ISparqlAlgebra Transform(IAlgebraOptimiser optimiser)
Parameters
Type Name Description
IAlgebraOptimiser optimiser Optimiser.
Returns
Type Description
ISparqlAlgebra

Implements

Extension Methods