Interface IVirtualRdfProvider<TNodeID, TGraphID>

A Virtual RDF Provider is a provider that transforms materialised values into virtual ID values. These virtual values can be used to do much faster term equality checking and to minimise memory usage when accessing out of memory data.

Namespace: VDS.RDF.Storage.Virtualisation

Assembly: dotNetRdf.dll

Syntax

public interface IVirtualRdfProvider<TNodeID, TGraphID>

Type Parameters

Name	Description
TNodeID	Node ID Type.
TGraphID	Graph ID Type.

Remarks

An implementation of this is typically in addition to a more general RDF store implementation (such as an IStorageProvider) and was originally designed and intended for use in creating ISparqlDataset instances which allow out of memory data to be queried more efficiently.

It is expected that most implementations will use a cache to ensure that repeated transformations are as fast as possible.

Important Note re: Blank Nodes

In order for code that uses this class to function correctly it must be ensured that IDs issued for Blank Nodes are graph scoped, as such a specific method for converting Blank Nodes into Virtual Node IDs is given.

Properties

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NullID

Gets the Node ID that is used to indicate that a Node does not exist in the underlying storage.

Declaration

TNodeID NullID { get; }

Property Value

Type	Description
TNodeID

Methods

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GetBlankNodeID(IBlankNode)

Given a Blank Node returns a Graph scoped Node ID.

Declaration

TNodeID GetBlankNodeID(IBlankNode value)

Parameters

Type	Name	Description
IBlankNode	value	Blank Node.

Returns

Type	Description
TNodeID

Remarks

Should function as equivalent to the two argument version with the createIfNotExists parameter set to false.

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GetBlankNodeID(IBlankNode, bool)

Given a Blank Node returns a Graph scoped Node ID.

Declaration

TNodeID GetBlankNodeID(IBlankNode value, bool createIfNotExists)

Parameters

Type	Name	Description
IBlankNode	value	Blank Node.
bool	createIfNotExists	Determines whether to create a new Node ID if there is not already one for the given value.

Returns

Type	Description
TNodeID

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GetGraphID(Uri)

Gets the Graph ID for a Graph URI.

Declaration

TGraphID GetGraphID(Uri graphUri)

Parameters

Type	Name	Description
Uri	graphUri	Graph URI.

Returns

Type	Description
TGraphID

Remarks

Should function as equivalent to the two argument version with the createIfNotExists parameter set to false.

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GetGraphID(Uri, bool)

Gets the Graph ID for a Graph URI.

Declaration

TGraphID GetGraphID(Uri graphUri, bool createIfNotExists)

Parameters

Type	Name	Description
Uri	graphUri	Graph URI.
bool	createIfNotExists	Determines whether to create a new Graph ID if there is not already one for the given Graph URI.

Returns

Type	Description
TGraphID

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GetGraphID(IGraph)

Gets the Graph ID for a Graph.

Declaration

TGraphID GetGraphID(IGraph g)

Parameters

Type	Name	Description
IGraph	g	Graph.

Returns

Type	Description
TGraphID

Remarks

Should function as equivalent to the two argument version with the createIfNotExists parameter set to false.

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GetGraphID(IGraph, bool)

Gets the Graph ID for a Graph creating it if necessary.

Declaration

TGraphID GetGraphID(IGraph g, bool createIfNotExists)

Parameters

Type	Name	Description
IGraph	g	Graph.
bool	createIfNotExists	Determines whether to create a new Graph ID if there is not already one for the given Graph.

Returns

Type	Description
TGraphID

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GetGraphUri(TGraphID)

Given a Graph ID returns the value of the Graph URI.

Declaration

Uri GetGraphUri(TGraphID id)

Parameters

Type	Name	Description
TGraphID	id	Graph ID.

Returns

Type	Description
Uri

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GetID(INode)

Given a non-blank Node returns the Node ID.

Declaration

TNodeID GetID(INode value)

Parameters

Type	Name	Description
INode	value	Node.

Returns

Type	Description
TNodeID

Remarks

Should function as equivalent to the two argument version with the createIfNotExists parameter set to false.

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GetID(INode, bool)

Given a non-blank Node returns the Node ID.

Declaration

TNodeID GetID(INode value, bool createIfNotExists)

Parameters

Type	Name	Description
INode	value	Node.
bool	createIfNotExists	Determines whether to create a new Node ID if there is not already one for the given value.

Returns

Type	Description
TNodeID

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GetValue(IGraph, TNodeID)

Given a Node ID returns the materialised value in the given Graph.

Declaration

INode GetValue(IGraph g, TNodeID id)

Parameters

Type	Name	Description
IGraph	g	Graph to create the Node in.
TNodeID	id	Node ID.

Returns

Type	Description
INode

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LoadGraphVirtual(IGraph, Uri)

Loads a Graph creating all the Triples with virtual node values.

Declaration

void LoadGraphVirtual(IGraph g, Uri graphUri)

Parameters

Type	Name	Description
IGraph	g	Graph to load into.
Uri	graphUri	URI of the Graph to load.

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)