SPARQL Stores

The SPARQL Stores settings view lets you manage triple store profiles. Each profile describes what a specific triple store can do — for example, whether it supports inferencing — and which queries it should use for automated tasks, like fetching the list of graphs.

Every SPARQL connection points to exactly one store profile. Whenever Mentor needs to run a query on your behalf — listing graphs, opening or deleting a graph, describing a resource — it takes the query from the store profile of the connection instead of assuming a particular vendor dialect.

The view is opened from the Command Palette (Ctrl+Shift+P) with the Mentor: Settings command, followed by selecting Query → Stores in the navigation:

The view is divided into four sections: Built-In, Community, Workspace and User.

Type	Description
Built-In	Vendor neutral store profiles that ship with Mentor: the generic SPARQL Endpoint profile and the Workspace profile of Mentor’s internal RDF triple store. They cannot be edited or removed.
Community	Store profiles for commonly used, and actively developed open source triple stores. Thanks to all the great people developing and maintaining these projects.
Workspace	Workspace stores are stored in the .vscode directory and can thus be shared with other users in version controlled repositories.
User	User stores are only available to the current user and are typically stored on the user’s local machine and can be synced across devices with Settings Sync.

Configuration Scopes

The Workspace section is only shown when a workspace folder is opened. A connection can only use a built-in or community store, or a store that is defined in its own configuration scope. A workspace connection can therefore not use a store from your user settings — such a store is listed in the connection’s Store dropdown, but disabled.

View Actions

Unlike the connections view, the stores view has no global title bar actions. Instead, each editable section has its own action in the section header:

Action	Description
Add Store	Configure a new SPARQL store profile in the configuration scope of the section it was invoked from.

Store Actions

When you select or hover a store in the list view, additional actions will become available in the store header:

Action	Description
Documentation	Open the configured documentation page for the store.
Delete Store	Deletes the selected SPARQL store.

Built-in and community stores are marked with a lock icon instead of the delete action. They can be opened and inspected, but not modified.

Editing Stores

When you select an existing store in the store manager or when you click on the ‘Add Store’ icon, the store details will be displayed in a new dialog window.

From here, you can modify the store settings, such as the name, documentation URL and other parameters. Once you have made your changes, you can save them to update the store:

The dialog groups the store settings into the three tabs General, Queries and Reasoning. The configuration scope of the store is selected next to the dialog title, the Save button and the Delete store action are located in the dialog header.

The following configuration options are available on the General tab:

Setting	Description
Name	The display name of the store profile. It is shown in the Store dropdown of the connection editor.
Description	An optional description which helps to keep store profiles apart. It is shown as the subline in the store list.
Documentation URL	An optional link to the documentation of the triple store. When set, the store list offers the Documentation action.

Changing the Configuration Scope

Moving a store from the user to the workspace settings (or the other way round) may break connections that still reference it from the other scope. Mentor warns you about the affected connections when you save the store; those connections fall back to the generic SPARQL defaults wherever the store is missing.

Reasoning

Many triple stores can include inferred triples in a query result, but there is no standardized way to request this. The Reasoning tab describes how the store expects reasoning to be switched on and off:

Setting	Description
Supports reasoning control per query	Indicates that the store can toggle reasoning per query. When disabled, all other fields on this tab are unavailable and connections using this store cannot toggle inference.
URL Parameters	Query-string fragment appended to the endpoint URL, for the Enabled and the Disabled state — for example infer=true and infer=false.
Query Pragma	Text prepended to the query, for the Enabled and the Disabled state — for example #pragma reasoning on and #pragma reasoning off.

Both channels are optional and can be combined; a field that is left empty is simply not applied.

Inference in Queries

Only when a store declares reasoning support, the connections using it offer the Enable query reasoning by default option, and SPARQL documents and notebook cells show the Inference code lens to toggle inference per document.

Editing Queries

Some of Mentor’s features are implemented as SPARQL queries that run against your endpoint. Because the required dialect differs between triple stores, each of these queries can be overridden per store profile on the Queries tab:

Select the query you want to change from the dropdown at the top of the tab. The following queries can be customized:

Query	Used for
List Graphs Query	Retrieves all named graphs of a store. Executed by the List Graphs action in the connections view and when the graphs of a connection are loaded automatically for auto-complete and linting.
Drop Graph Query	Removes a named graph from the store. Executed from the graph list in the SPARQL results view.
Describe Resource Query	Retrieves the description of a resource. Executed by the Describe Resource command in the editor context menu and in the Definitions Tree.
Export Graph Query	Exports a named graph as Turtle when you open a graph from the graph list.
Count Graphs Query	Determines the size of a graph before it is exported, so that Mentor can warn you about very large graphs.

A query that is not overridden falls back to the global default. Mentor indicates this by rendering the preview muted, with the hint Showing the global default. As soon as you change the query, it becomes a store-specific override — use Reset to Default in the preview to remove it again.

The Triplate Workflow

Except for the List Graphs Query, all of these queries receive parameters from Mentor. They are therefore not plain SPARQL queries, but Triplate templates: a typed --- frontmatter header declares the parameters, and the query body interpolates them injection-safe with ${…}.

Editing a query template works like this:

1. Click on the query preview on the Queries tab. The template opens in a real editor tab beside the settings, so you get syntax highlighting, diagnostics and code lenses instead of a plain text box.

   

2. Edit the template. The params { … } block in the frontmatter declares which values the template accepts, the body is ordinary SPARQL with ${…} interpolations and {% if %} / {% for %} control flow:

   ---
   params {
     graphIri: iri
   }
   ---
   CONSTRUCT {
       ?s ?p ?o .
   } WHERE {
       GRAPH ${graphIri} {
           ?s ?p ?o .
       }
   }

3. Optionally declare one or more example blocks in the frontmatter to try the template out with concrete values. An example has an identifier, an optional description and a value for each parameter:

   ---
   params {
     graphIri: iri
   }
   example skos "Export the SKOS vocabulary" {
     graphIri: <http://www.w3.org/2004/02/skos/core>
   }
   ---
   CONSTRUCT {
       ?s ?p ?o .
   } WHERE {
       GRAPH ${graphIri} {
           ?s ?p ?o .
       }
   }

4. Use the Run code lens to render and execute the template. The lens at the top of the file asks for the parameter values — or lets you pick one of the declared examples — while the lens above an example block runs that example directly. The rendered query is executed against the endpoint shown in the Connections Lens of the editor, which is the internal workspace store by default.

   

5. Save the editor (Ctrl+S on Windows/Linux, Cmd+S on macOS) to hand the template back to the store dialog. The preview on the Queries tab is updated immediately.

6. Save the store in the dialog header to persist the override in your user or workspace settings.

Parameter Names

Mentor passes the parameters of a query by name. A custom template must declare all parameters listed below in its params block — even the ones the query body does not use — because Triplate rejects a value that is not declared with an unknown parameter error at runtime. Renaming a parameter has the same effect.

Query	Parameters	Expected Result
List Graphs Query	none	Bindings whose first variable is the graph IRI.
Drop Graph Query	graphIri: iri	A SPARQL update.
Describe Resource Query	resourceIri: iri, graphIris: iri[] optional	RDF triples (CONSTRUCT or DESCRIBE).
Export Graph Query	graphIri: iri	RDF triples (CONSTRUCT or DESCRIBE).
Count Graphs Query	graphIri: iri, limit: int optional	A single binding named ?count.

Triplate

Triplate is not limited to store queries — you can use it in any SPARQL, Turtle or TriG document and in Mentor notebooks. The full language guide and specification is available at triplate.dev.

Deleting Stores

To delete a store from the stores view you can either use the icon in the store manager or click on the same icon in the store detail view. Built-in and community stores cannot be deleted.

When asked, confirm the deletion when prompted. Please keep in mind that once a store is deleted, it cannot be recovered, so make sure you really want to delete it before confirming.

If the store is still used by SPARQL connections, Mentor lists the affected connections and offers two ways to resolve this:

Action	Description
OK	Deletes the store and switches the affected connections to the generic SPARQL Endpoint store.
Delete Connections	Deletes the store together with all connections that use it.

Settings

Store profiles and the global defaults of the store queries are kept in the following settings:

mentor.sparql.storesThe user and workspace defined store profiles. Built-in and community stores are not part of this setting.

mentor.sparql.listGraphsQuerySPARQL query used to retrieve all named graphs and the default graph from a store.

mentor.sparql.dropGraphQuerySPARQL query template used to remove a named graph from a store.

mentor.sparql.describeQueryTemplateSPARQL query template used by the describe resources command.

mentor.sparql.exportGraphQuerySPARQL query template used to export a named graph as Turtle.

mentor.sparql.countGraphQuerySPARQL query template used to check graph size before export.