Resource Description Framework

Using the Data Services Server, you can create a data service using a RDF (Resource Description Framework) as the data source.

1. Log on to the Data Services Server Management Console.

2. Click the Main tab and select the Create link under Data Services.

3. The Create Data Service page appears. Fill in the fields and click Next. The Data Service name is mandatory.

Info:
For more information on Advanced Configurations in creating data services, refer to the Transaction Handling section.

4. The Data Sources page appears. Click on the Add New Data Source link and add your Data Source details. Select the data source type as RDF.

For example,

Note:
We use a sample resource hosted online but you can also use one in your local machine. The RDF resource used in this example is hosted by NASA in this URL: http://nasa.dataincubator.org/~search.rdf?query=all

Click Save.

5. The added data source page appears. You can edit or delete the Data Source. To proceed click Next.

6. The Queries page appears.

Initially your service does not include any queries. Click 'Add New Query' to add a new query, input/output mappings, events etc. to your Data Service. Enter query details according to the structure of the response you want.

In this example, we have used the following SPARQL query to extract the specific aircraft information from the data source.

PREFIX space: <http://purl.org/net/schemas/space/>
PREFIX relevance: <http://a9.com/-/opensearch/extensions/relevance/1.0/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dc: <http://purl.org/dc/elements/1.1/>

SELECT ?homepage ?name ?alternateName ?internationalDesignator ?mass ?score ?launch ?agency ?description
WHERE {
  ?craft foaf:homepage ?homepage.
  ?craft foaf:name ?name.
  ?craft space:alternateName ?alternateName.
  ?craft space:internationalDesignator ?internationalDesignator.
  ?craft space:mass ?mass.
  ?craft relevance:score ?score.
  ?craft space:launch ?launch.
  ?craft space:agency ?agency.
  ?craft dc:description ?description.
}

The input mapping section is used to specify parameters to the query. The above query extracts aircraft information according to the agency. Therefore, we take agency as an input parameter. Input parameters can be added by clicking Add Input Mappings.

We have also used the Grouped By Element Grouped By Element, Row Name and Row namespace.

Click on Add Output Mappings to map the response to an output XML. Once you have entered the output mapping details, click on Main Configuration and then the Save button.

The output mappings:

For information on adding validations to input mappings in the query, if any, refer to section Input Validators.

7. You have added one query to your data service configuration.

You can edit or delete your query. To continue, click Next.

8. The Operations page appears. Click the Add new operation link to create an operation. Select a query to be executed when this operation is called.

Click Save once done. For example,

9. The Data Service configuration is done. Click Finish. (You can continue to add resources by clicking the Next button if you like)

10. You will be navigated to the "Deployed services" page.

From here, you can manage your service.