Class Ask

Represents the Ask step of Query Evaluation.

Inheritance
object
Ask
Implements
Inherited Members
Namespace: VDS.RDF.Query.Algebra
Assembly: dotNetRdf.dll
Syntax
public class Ask : IUnaryOperator, ISparqlAlgebra, IVisitable, IProcessable
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

| Edit this page View Source

Ask(ISparqlAlgebra)

Creates a new ASK.

Declaration
public Ask(ISparqlAlgebra pattern)
Parameters
Type Name Description
ISparqlAlgebra pattern

Inner Pattern.

Properties

| Edit this page View Source

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
IEnumerable<string>
| Edit this page View Source

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
IEnumerable<string>
| Edit this page View Source

InnerAlgebra

Gets the Inner Algebra.

Declaration
public ISparqlAlgebra InnerAlgebra { get; }
Property Value
Type Description
ISparqlAlgebra
| Edit this page View Source

Variables

Gets the Variables used in the Algebra.

Declaration
public IEnumerable<string> Variables { get; }
Property Value
Type Description
IEnumerable<string>

Methods

| Edit this page View Source

Accept<T>(ISparqlAlgebraVisitor<T>)

Accept a simple algebra visitor.

Declaration
public T Accept<T>(ISparqlAlgebraVisitor<T> visitor)
Parameters
Type Name Description
ISparqlAlgebraVisitor<T> visitor

The visitor implementation.
Returns
Type Description
T
Type Parameters
Name Description
T

The type returned by the Visit methods of the visitor.
| Edit this page View Source

Accept<TResult, TContext>(ISparqlQueryAlgebraProcessor<TResult, TContext>, TContext)

Called by an algebra visitor to process an item by invoking the appropriate method on the processor passed in.

Declaration
public TResult Accept<TResult, TContext>(ISparqlQueryAlgebraProcessor<TResult, TContext> processor, TContext context)
Parameters
Type Name Description
ISparqlQueryAlgebraProcessor<TResult, TContext> processor

The processor to invoke.
TContext context

The context to pass to the processor.
Returns
Type Description
TResult

The result of invoking the processor method.
Type Parameters
Name Description
TResult

The type of result returned by the processor.
TContext

The type of the context object to be provided to the processor.
| Edit this page View Source

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
NotSupportedException

Thrown since an Ask() cannot be converted to a Graph Pattern.
| Edit this page View Source

ToQuery()

Converts the Algebra back to a SPARQL Query.

Declaration
public SparqlQuery ToQuery()
Returns
Type Description
SparqlQuery
| Edit this page View Source

ToString()

Gets the String representation of the Ask.

Declaration
public override string ToString()
Returns
Type Description
string
Overrides
| Edit this page View Source

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