External Datasource

Description

A Datasource is a SPARQL endpoint service that gives you the ability to define and access additional repositories within a single origin. For example /sparql is the Datasource that gives you read/write access to the default Sesame repository that Callimachus uses. By creating a new Datasource you are creating a certain repository with custom configuration. That repository can be externally hosted.

Managing Datasources

Creating a Datasource

Step	Action
1	If using an external repository, ensure it is currently running and available
2	Configure external repository with any additional settings necessary to accept an external connection
3	Navigate to the Server object that is currently connected to the operational Callimachus Enterprise instance
4	Click the "Edit" tab and then click the edit (pencil) icon next to the realm you wish to configure
5	Click the new window icon next to "Datasources" and fill out the form with the appropriate values
6	Hit "Create" to create the Datasource, then "Save" to save the Deployment, then "Save Settings" to save the configuration of the server.

The following fields are avialable when configuring a new Datasource and/or replacing an existing Datasource.

Field	Description	Sample Value
Service Endpoint URL	This is the URL where the datasource will be accessed. This URL must start with the same host name as your Callimachus Instance.	http://example.com/data
Repository Config	This is the Sesame configuration file that describes to Callimachus exactly where the repository is located and how it will be configured.
Languages	Checking SPARQL Query allows Read operations to be performed against the Datasource. Checking SPARQL Update allows Write operations to be performed against the Datasource.
Entailment	The Entailment checkboxes serve as a form of documentation that states certain attributes about the Datasource. Full documentation on the different types of Entailment can be found here.
Features	These features can be enabled or disabled for your Datasource. Full documentation on the different features can be found here.

Note: If you want to modify this Datasource programmatically (i.e. from a Pipeline) you will need to set the Permissions for the Datasource so that the System group is listed under "Editor".

Editing a Datasource

Once a Datasource has been created you can go back and edit any of the values you entered by selecting the "Edit" tab when viewing the Datasource. You can change both the Label and the Comment as well as whether or not Read and Write operations can be performed against the Datasource.

Deleting a Datasource

You can delete a Datasource at any time by navigating to the "Edit" tab of the desired Datasource.

Note: This does NOT delete any underyling data in external datastores. It simply deletes the SPARQL endpoint service on the Callimachus side.

Using a Datasource

Callimachus Datasources expose all SPARQL 1.1 commands. The most common you probably will find yourself using to get started are LOAD and SELECT. The interface is just a large textarea in which you can type your commands. If you are working with a small dataset you can perform the following query to ensure the Datasource is working as expected:

SELECT DISTINCT ?type WHERE { 
    ?thing a ?type 
} ORDER BY ?type LIMIT 50

Oops!