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FAQ
Frequently asked questions about SPARQLWorks™ and their answers.
SPARQLWorks is a web-based application for composing, running, and visualizing SPARQL queries against any SPARQL 1.1 compliant endpoint. It transforms query results into interactive knowledge graphs using D3.js visualization.
No installation required! SPARQLWorks runs entirely in your web browser. Just open the URL and start querying.
SPARQLWorks works in all modern browsers:
- Chrome 80+
- Firefox 75+
- Safari 13+
- Edge 80+
- Mobile browsers with modern JavaScript support
- Basic Mode: User-friendly interface for simple queries. You write WHERE clauses and SPARQLWorks automatically generates the full CONSTRUCT query.
- Advanced Mode: Full SPARQL editor for complex queries, custom constructs, and advanced SPARQL features.
Yes! SPARQLWorks works with any SPARQL 1.1 compliant endpoint that supports JSON-LD output format. Popular endpoints include Wikidata, DBpedia, and custom enterprise endpoints. Additional output formats will be supported in the future.
Basic mode uses simple triple patterns:
?movie dbo:creator ?creator;
rdfs:label ?movieName.
FILTER(?creator = dbr:Spike_Lee)
SPARQLWorks converts this into a complete CONSTRUCT query automatically.
Default limit is 200 results. You can adjust this in Basic mode (1-10000) or set it explicitly in Advanced mode queries.
Possible causes:
- No results: Your query returned no data - try broadening the WHERE clause
- Filtering: Active filters may be hiding all nodes
- Endpoint issues: Check if the endpoint is accessible
- Authentication: Some endpoints require login and/or have ACL protected content
- Zoom: Mouse wheel or pinch gestures
- Pan: Click and drag empty space
- Fit: Click "Fit" button to see entire graph
- Hover focus: Hover over nodes to highlight connections
- Filters: Use type/property filters to reduce complexity
- Blue: IRI entities (persons, places, organizations)
- Green: RDF classes and types
- Orange: Categories and classifications
- Purple: Roles and functions
- Gray: Literal values (strings, numbers, dates)
Node sizes are automatic based on type:
- Classes: Largest (18px)
- Roles: Large (16px)
- Entities: Medium (14px)
- Literals: Small (10px)
SPARQLWorks supports two authentication methods:
- OAuth 2.0: Modern, secure authentication with PKCE
- Bearer tokens: Direct token input
- OAuth: Browser-based login flow, secure and standard
- Bearer: Manual token entry, simpler but requires token management
OAuth 2.0 security requires HTTPS to prevent token interception. The application must be served over HTTPS for OAuth to work.
Yes, but they will return empty or reduced results if the recipient does not have the same granted access. Authentication credentials are not included in shareable URLs for security reasons. Recipients must authenticate separately.
All settings are automatically saved in your browser's local storage and persist between sessions.
Yes, in browser console:
localStorage.clear();
location.reload();- Click the gear icon next to "Use IRI Labels"
- Drag predicates to reorder priority
- Click "Save" to apply changes
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IRI Labels: Show compact CURIEs (e.g.,
dbr:Apple_Inc.) - Friendly Labels: Show human-readable names from schema:name, rdfs:label, etc.
Click the link icon (🔗) next to the controls toggle. This copies a complete URL with your query and settings to the clipboard.
Everything: query, endpoint, filters, physics settings, visualization preferences, and node positions.
SPARQLWorks encodes the complete application state, including the full SPARQL query and all settings. This ensures exact reproduction.
Yes! Shared URLs are bookmarkable and will restore the exact state when opened.
- Check query syntax in Advanced mode
- Verify endpoint URL is correct and accessible
- Ensure proper authentication if required
- Try a simpler query first
- Remove FILTER clauses that might be too restrictive
- Check if the endpoint has the expected data
- Verify namespace prefixes are correct
- Try increasing the LIMIT
- Reduce graph size with LIMIT or filters
- Close other browser tabs
- Clear browser cache
- Try a different browser
- Click the gear icon (⚙️) in the top-right
- Check if popup blockers are interfering
- Try refreshing the page
- Ensure HTTPS for OAuth
- Check redirect URI configuration
- Verify endpoint supports chosen auth method
- Try clearing browser data for the domain
SPARQLWorks can handle thousands of nodes, but performance depends on your device.
- Use LIMIT to reduce result size
- Apply filters before visualization
- Close the query panel when exploring
- Use simpler physics settings
- Disable hover focus for large graphs
Large graphs require significant memory and processing. Try:
- Reducing node count
- Using filters to focus on relevant data
- Closing other applications
- Using a more powerful device
Yes! In Both Basic and Advanced mode, you can define custom prefixes:
PREFIX my: <http://example.com/my-schema#>
CONSTRUCT { ?s my:property ?o }
WHERE { ?s my:property ?o }Currently, SPARQLWorks focuses on visualization. For data export, use the underlying SPARQL endpoint directly or implement custom export functionality.
The application is designed as a standalone tool, but you can:
- Link to specific queries via URL parameters
- Embed in iframes (with proper CORS setup)
- Integrate via API if you extend the application
- Default: Opens IRIs directly in the browser
- Virtuoso: Opens entity description pages using the endpoint's describe service
No! SPARQLWorks processes everything in your browser. Queries go directly to the SPARQL endpoint you specify.
SPARQLWorks relies on SPARQL endpoints supporting CORS. Some endpoints may require proxy configuration for browser access.
- Frontend: Vanilla JavaScript (ES6+)
- Visualization: D3.js v7
- Styling: Tailwind CSS
- Editor: Ace Editor
- Data: JSON-LD, RDF
- Check existing issues on the project repository
- Create a new issue with detailed information
- Include browser, endpoint, and steps to reproduce
- Browser and version
- SPARQL endpoint URL
- Exact query that fails
- Error messages or screenshots
- Steps to reproduce the issue
Yes! SPARQLWorks is open source. Contributions are welcome for:
- Bug fixes
- New features
- Documentation improvements
- Performance optimizations