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, Boolean)

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.
System.Boolean 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
System.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, Boolean)

Gets the Graph ID for a Graph URI.
Declaration
TGraphID GetGraphID(Uri graphUri, bool createIfNotExists)
Parameters
Type Name Description
System.Uri graphUri Graph URI.
System.Boolean 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, Boolean)

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.
System.Boolean 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
System.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, Boolean)

Given a non-blank Node returns the Node ID.
Declaration
TNodeID GetID(INode value, bool createIfNotExists)
Parameters
Type Name Description
INode value Node.
System.Boolean 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.
System.Uri graphUri URI of the Graph to load.

Extension Methods