Semantic Databases

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Expertise and RDF Services from Semweb

Semantic Databases – RDF Stores

Semantic data are stored nowadays in RDF stores – semantic databases – and are queried by humans or by programs by means of query languages like SPARQL to get logical connections among several semantic graphs or even among different semantic databases, giving a method to access data and meaning across several data sources.

Semweb supports you during the phases of selecting and integrating your RDF store. Take a look at some of the best RDF stores through their SPARQL endpoints: Bigdata™ (SSL), Stardog (SSL), GraphDB™ (SSL), MarkLogic™, Virtuoso™.

Tutorial: follow the loupe (on top left besides this text in a maximized browser.)

Let yourself go (Notes)

Start HTTP Demo

Quick Start

  1. Choose your semantic database system
  2. Formulate your SPARQL query in its query field
  3. Execute the query
  4. Browse the results
  5. Use the provided examples
Details

  1. Select one tab in the gray tab bar below to change / show the SPARQL endpoint panel of one semantic database system (e.g. GraphDB or Bigdata)
  2. Identify the query field. Each system has a slightly different way to describe it:
    - on Bigdata im Unter-Tab "QUERY": take here the biggest input field
    - on Stardog: "_Query"
    - on GraphDB: "Query"
    - on MarkLogic: "Query1" - Please consider setting here the following parameters:
       + Content Source must be on "RDFsamples"
       + Query Type must be on "SPARQL"
    - on Virtuoso: "Query Text"
  3. Press a run/execute button in that panel to execute the SPARQL query:
    - on Bigdata im Unter-Tab "QUERY": "Execute"
    - on Stardog: "Execute"
    - on GraphDB: "Execute"
    - on Marklogic: "Run"
    - on Virtuoso "Run Query"
  4. The RDF results are displayed as list of triples. Some systems (Mainly GraphDB) allow you to browse among the results.
  5. In case you want to use the prepared SPARQL queries - please click on "Examples ...", then copy&paste the query to the query field in the endpoint panel