Class SparqlQuery

Represents a SPARQL Query.

Inheritance

object

SparqlQuery

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

Namespace: VDS.RDF.Query

Assembly: dotNetRdf.dll

Syntax

public sealed class SparqlQuery

Remarks

Note: This class is purposefully sealed and most setters are private/protected internal since generally you create a query by using the SparqlQueryParser to parse a query string/file.

To build a query programmatically you can use the QueryBuilder class to generate a new query and then various extension methods to modify that query using a fluent style API. A query is not immutable so if you use that API you are modifying the query, if you want to generate new queries by modifying an existing query consider using the Copy() method to take a copy of the existing query.

Constructors

SparqlQuery(bool)

Creates a new SPARQL Query.

Declaration

public SparqlQuery(bool subQuery)

Parameters

Type	Name	Description
bool	subQuery	Whether this query is a sub-query.

Properties

AlgebraOptimisers

Gets/Sets the locally scoped Algebra Optimisers that are used to optimise the Query Algebra in addition to (but before) any external (e.g. processor-provided) optimisers.

Declaration

public IEnumerable<IAlgebraOptimiser> AlgebraOptimisers { get; set; }

Property Value

Type	Description
IEnumerable<IAlgebraOptimiser>

BaseUri

Get or set the base URI used to resolve relative URI references.

Declaration

public Uri BaseUri { get; set; }

Property Value

Type	Description
Uri

Bindings

Gets/Sets the VALUES Clause for the Query which are bindings that should be applied.

Declaration

public BindingsPattern Bindings { get; }

Property Value

Type	Description
BindingsPattern

ConstructTemplate

Gets/Sets the Construct Template for a Construct Query.

Declaration

public GraphPattern ConstructTemplate { get; }

Property Value

Type	Description
GraphPattern

DefaultGraphNames

Gets the names of the default graphs for the query.

Declaration

public IEnumerable<IRefNode> DefaultGraphNames { get; }

Property Value

Type	Description
IEnumerable<IRefNode>

DefaultGraphs

Gets the Default Graph URIs for the Query.

Declaration

[Obsolete("Replaced by DefaultGraphNames")]
public IEnumerable<Uri> DefaultGraphs { get; }

Property Value

Type	Description
IEnumerable<Uri>

DescribeVariables

Gets the Variables, QNames and URIs used in the Describe Query.

Declaration

public IEnumerable<IToken> DescribeVariables { get; }

Property Value

Type	Description
IEnumerable<IToken>

ExpressionFactories

Gets/Sets the locally scoped Expression Factories that may be used if the query is using the CALL() function to do dynamic function invocation.

Declaration

public IEnumerable<ISparqlCustomExpressionFactory> ExpressionFactories { get; set; }

Property Value

Type	Description
IEnumerable<ISparqlCustomExpressionFactory>

GroupBy

Gets/Sets the Grouping for the Query.

Declaration

public ISparqlGroupBy GroupBy { get; }

Property Value

Type	Description
ISparqlGroupBy

HasDistinctModifier

Gets whether a Query has a DISTINCT modifier.

Declaration

public bool HasDistinctModifier { get; }

Property Value

Type	Description
bool

HasSolutionModifier

Gets whether the Query has a Solution Modifier (a GROUP BY, HAVING, ORDER BY, LIMIT or OFFSET).

Declaration

public bool HasSolutionModifier { get; }

Property Value

Type	Description
bool

Having

Gets/Sets the Having Clause for the Query.

Declaration

public ISparqlFilter Having { get; }

Property Value

Type	Description
ISparqlFilter

IsAggregate

Gets whether the Query has an Aggregate as its Result.

Declaration

public bool IsAggregate { get; }

Property Value

Type	Description
bool

IsOptimised

Gets whether Optimisation has been applied to the query.

Declaration

public bool IsOptimised { get; }

Property Value

Type	Description
bool

Remarks

This only indicates that an Optimiser has been applied. You can always reoptimise the query using a different optimiser by using the relevant overload of the Optimise() method.

IsSubQuery

Gets whether this Query is a Sub-Query in another Query.

Declaration

public bool IsSubQuery { get; }

Property Value

Type	Description
bool

Limit

Gets the Result Set Limit for the Query.

Declaration

public int Limit { get; set; }

Property Value

Type	Description
int

Remarks

Values less than zero are counted as -1 which indicates no limit.

NamedGraphNames

Gets the names of the named graphs for the query.

Declaration

public IEnumerable<IRefNode> NamedGraphNames { get; }

Property Value

Type	Description
IEnumerable<IRefNode>

NamedGraphs

Gets the Named Graph URIs for the Query.

Declaration

[Obsolete("Replaced by NamedGraphNames")]
public IEnumerable<Uri> NamedGraphs { get; }

Property Value

Type	Description
IEnumerable<Uri>

NamespaceMap

Gets the map of namespace prefixes to URIs.

Declaration

public INamespaceMapper NamespaceMap { get; }

Property Value

Type	Description
INamespaceMapper

Offset

Gets/Sets the Result Set Offset for the Query.

Declaration

public int Offset { get; set; }

Property Value

Type	Description
int

Remarks

Values less than zero are treated as 0 which indicates no offset.

OrderBy

Gets/Sets the Ordering for the Query.

Declaration

public ISparqlOrderBy OrderBy { get; }

Property Value

Type	Description
ISparqlOrderBy

PartialResultsOnTimeout

Gets/Sets whether Partial Results should be returned in the event of Query Timeout.

Declaration

public bool PartialResultsOnTimeout { get; set; }

Property Value

Type	Description
bool

Remarks

Partial Results (typically) only applies when executing the Query in memory. If you have an instance of this class and pass its string representation (using ToString()) you will lose the partial results information as this is not serialisable in SPARQL syntax.

PropertyFunctionFactories

Gets/Sets the locally scoped Property Function factories that may be used by the PropertyFunctionOptimiser when generating the algebra for the query.

Declaration

public IEnumerable<IPropertyFunctionFactory> PropertyFunctionFactories { get; set; }

Property Value

Type	Description
IEnumerable<IPropertyFunctionFactory>

QueryExecutionTime

Gets the Time taken to execute a Query.

Declaration

public TimeSpan? QueryExecutionTime { get; set; }

Property Value

Type	Description
TimeSpan?

Exceptions

Type	Condition
InvalidOperationException	Thrown if you try and inspect the execution time before the Query has been executed.

QueryType

Gets the type of the Query.

Declaration

public SparqlQueryType QueryType { get; }

Property Value

Type	Description
SparqlQueryType

RootGraphPattern

Gets the top level Graph Pattern of the Query.

Declaration

public GraphPattern RootGraphPattern { get; }

Property Value

Type	Description
GraphPattern

SpecialType

Gets the Special Type of the Query (if any).

Declaration

public SparqlSpecialQueryType SpecialType { get; }

Property Value

Type	Description
SparqlSpecialQueryType

Timeout

Gets/Sets the Query Execution Timeout in milliseconds.

Declaration

public long Timeout { get; set; }

Property Value

Type	Description
long

Remarks

This Timeout (typically) only applies when executing the Query in memory. If you have an instance of this class and pass its string representation (using ToString()) you will lose the timeout information as this is not serialisable in SPARQL syntax.

UsesDefaultDataset

Gets whether a Query uses the Default Dataset against which it is evaluated.

Declaration

public bool UsesDefaultDataset { get; }

Property Value

Type	Description
bool

Remarks

If the value is true then the Query will use whatever dataset is it evaluated against. If the value is false then the query changes the dataset at one/more points during its evaluation.

Things that may change the dataset and cause a query not to use the Default Dataset are as follows:.

• FROM clauses (but not FROM NAMED)
• GRAPH clauses
• Subqueries which do not use the default dataset

Variables

Gets the Variables used in the Query.

Declaration

public IEnumerable<SparqlVariable> Variables { get; }

Property Value

Type	Description
IEnumerable<SparqlVariable>

VirtualCount

The number of results that would be returned without any limit clause to a query or -1 if not supported. Defaults to the same value as the Count member.

Declaration

[Obsolete("This property is obsolete and is no longer set when a query is processed")]
public int VirtualCount { get; }

Property Value

Type	Description
int

Methods

AddDefaultGraph(Uri)

Adds a Default Graph URI.

Declaration

[Obsolete("Replaced by AddDefaultGraph(IRefNode)")]
public void AddDefaultGraph(Uri u)

Parameters

Type	Name	Description
Uri	u	Graph URI.

AddDefaultGraph(IRefNode)

Adds a graph to the default graph of the query.

Declaration

public void AddDefaultGraph(IRefNode n)

Parameters

Type	Name	Description
IRefNode	n

AddNamedGraph(Uri)

Adds a Named Graph URI.

Declaration

[Obsolete("Replaced by AddNamedGraph(IRefNode)")]
public void AddNamedGraph(Uri u)

Parameters

Type	Name	Description
Uri	u	Graph URI.

AddNamedGraph(IRefNode)

Adds a named graph to the query.

Declaration

public void AddNamedGraph(IRefNode n)

Parameters

Type	Name	Description
IRefNode	n

ClearDefaultGraphs()

Removes all Default Graph URIs.

Declaration

public void ClearDefaultGraphs()

ClearNamedGraphs()

Removes all Named Graph URIs.

Declaration

public void ClearNamedGraphs()

Copy()

Creates a copy of the query.

Declaration

public SparqlQuery Copy()

Returns

Type	Description
SparqlQuery

FromServiceQuery(GraphPattern, int)

Create a query instance that can be passed to remote endpoint when processing a SERVICE clause in a SPARQL Query.

Declaration

public static SparqlQuery FromServiceQuery(GraphPattern serviceGraphPattern, int limit)

Parameters

Type	Name	Description
GraphPattern	serviceGraphPattern	The root graph pattern of the SERVICE query.
int	limit	The limit on the number of results requested.

Returns

Type	Description
SparqlQuery

Optimise()

Applies optimisation to a Query using the default global optimiser.

Declaration

public void Optimise()

Optimise(IQueryOptimiser)

Applies optimisation to a Query using the specific optimiser.

Declaration

public void Optimise(IQueryOptimiser optimiser)

Parameters

Type	Name	Description
IQueryOptimiser	optimiser	Query Optimiser.

Process(ISparqlQueryProcessor)

Processes the Query using the given Query Processor.

Declaration

public object Process(ISparqlQueryProcessor processor)

Parameters

Type	Name	Description
ISparqlQueryProcessor	processor	SPARQL Query Processor.

Returns

Type	Description
object

ToAlgebra(bool, IEnumerable<IAlgebraOptimiser>)

Converts the Query into it's SPARQL Algebra representation (as represented in the Leviathan API).

Declaration

public ISparqlAlgebra ToAlgebra(bool optimise = true, IEnumerable<IAlgebraOptimiser> optimisers = null)

Parameters

Type	Name	Description
bool	optimise	Boolean flag indicating whether to apply algebra optimisation.
IEnumerable<IAlgebraOptimiser>	optimisers	The external algebra optimisers to apply.

Returns

Type	Description
ISparqlAlgebra

Remarks

If optimisers is null, only any locally defined optimisation will be applied.

ToString()

Generates a String representation of the Query.

Declaration

public override string ToString()

Returns

Type	Description
string

Overrides

object.ToString()

Remarks

This method may not return a complete representation of the Query depending on the Query it is called on as not all the classes which can be included in a Sparql query currently implement ToString methods.

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)