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Data Reference Management

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Peter Ansell edited this page Nov 1, 2013 · 1 revision

This page contains details about how PODD manages references to externally stored data items.

Artifacts that are stored in PODD can refer to various files/resources that are stored in external repositories. A PODD Data Reference is the mechanism used in PODD to refer to these external data items.

Data Reference Structure (in RDF/XML)

Example 1: Reference to a file that is a resource accessible via SSH

<rdf:Description rdf:about="http://example.org/purl/fileref:a2cb6e08-6388-40b8-86f1-cf9ea5e05b46">
    <rdf:type rdf:resource="http://purl.org/podd/ns/poddBase#DataReference"/>
    <rdf:type rdf:resource="http://purl.org/podd/ns/poddBase#SSHFileReference"/>
    <rdfs:label>Rice tree scan 003454-98</rdfs:label>
    <poddBase:hasAlias>csiro_dap</poddBase:hasAlias>
    <poddBase:hasFileName>plant_20121120_018503_AB.png</poddBase:hasFileName>
    <poddBase:hasPath>/machine1/pl/</poddBase:hasPath>
</rdf:Description>

The following excerpt shows how the above Data Reference is linked from another PODD object.

<rdf:Description rdf:about="http://example.org/purl/95944cb6-03d5-41d7-a371-315bbe2ea0ec/object:1960">
    <poddBase:hasDataReference rdf:resource="http://example.org/purl/fileref:a2cb6e08-6388-40b8-86f1-cf9ea5e05b46"/>
    ...
</rdf:Description>

The alias in the above RDF fragment is used by PODD to locate the external data repository for managing access to it. Data Repository Management in PODD is described [here](Data Repository Management).

Old Examples from the Prototype

Example 1: Reference to a file that is an HTTP resource

<rdf:Description rdf:about="http://podd.org/filereference#unique_random_id:2">
    <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Thing"/>
    <rdf:type rdf:resource="http://purl.org/podd/ns/poddBase#FileReference"/>
    <poddBase:hasFileReferenceType>HTTP</poddBase:hasFileReferenceType>
    <poddBase:hasFileName>rfc2616.html</poddBase:hasFileName>
    <poddBase:hasDescription>The http RFC</poddBase:hasDescription>
    <poddBase:hasPath>Protocols/rfc2616</poddBase:hasPath>
    <poddBase:hasAlias>w3</poddBase:hasAlias>
</rdf:Description>

Example 2: Reference to a file that is accessible over SSH

<rdf:Description rdf:about="http://example.org/permanenturl/fileref:a2cb6e08-6388-40b8-86f1-cf9ea5e05b46">
    <rdf:type rdf:resource="http://purl.org/podd/ns/poddBase#FileReference"/>
    <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
    <poddBase:hasFileReferenceType>SSH</poddBase:hasFileReferenceType>
    <hasAlias>csiro_dap</hasAlias>
    <hasDescription>plant image</hasDescription>
    <hasFileName>plant_20121120_018503_AB.png</hasFileName>
    <hasPath>/machine1/pl/</hasPath>
</rdf:Description>

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