Data Twingler Skill for SQL, SPARQL, and GraphQL

Execute SQL, SPARQL, SPASQL, SPARQL-FED, and GraphQL queries against live data spaces and knowledge graphs via OpenLink's OpenAPI-compliant web services. Use this skill whenever the user wants to query a database, RDF store, or SPARQL endpoint; explore a knowledge graph or data space; asks "How to ...", "Define the term ...", or poses a question against a known article or graph context; or mentions linkeddata.uriburner.com, Virtuoso, OPAL, or OpenLink services. Full query templates are in references/query-templates.md — load that file before constructing any predefined query.

OpenLink Data Twingler (v2.0.83)

Enhances LLM responses with RAG by routing user intent to the right query language and live endpoint. Covers SQL, SPARQL, SPASQL, SPARQL-FED, and GraphQL — all driven by natural language, no imperative programming required.

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Defaults & Settings

Parameter	Value
SPARQL Default Endpoint	https://linkeddata.uriburner.com/sparql
SPARQL Result Format	text/x-html+tr
SPARQL / SQL Timeout	30 seconds
SPARQL Max Results	20 (unless overridden)
GraphQL Default Endpoint	https://linkeddata.uriburner.com/graphql
GraphQL Query Depth Limit	10
SQL Default	SELECT TOP 20 * FROM Demo.Demo.Customers
Cache TTL	3600 seconds
Parallel Execution	Enabled
Tabulate All Results	Yes (all query types)

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Query Language Routing

Execution Routing

Default execution order for query execution:

1. Direct native endpoint calls with curl or the query protocol's simplest direct mechanism
2. URIBurner REST functions such as sparqlRemoteQuery, sparqlQuery, graphqlEndpointQuery, graphqlQuery, execute_spasql_query, and execute_sql_query
3. MCP via https://linkeddata.uriburner.com/chat/mcp/messages or https://linkeddata.uriburner.com/chat/mcp/sse
4. Authenticated LLM-mediated execution via https://linkeddata.uriburner.com/chat/functions/chatPromptComplete
5. OPAL Agent routing using recognizable OPAL function names

If the user's prompt expresses a protocol preference such as curl, REST, OpenAI, MCP, SSE, streamable HTTP, or OPAL, follow that preference instead of the default order.

Read references/protocol-routing.md when you need exact routing guidance.

SQL

Default: SELECT TOP 20 * FROM Demo.Demo.Customers Apply TOP 20 unless a row limit is specified. Tabulate results.

SPARQL

Use default endpoint. Format text/x-html+tr. Max 20 rows. Tabulate results.

SPARQL-FED

Trigger: User explicitly names a SPARQL endpoint URL in the prompt.

• Named endpoint → SERVICE block (remote); default endpoint → outer processor.
• SERVICE block must contain a SELECT with an inner LIMIT.

SPASQL

Wraps SPARQL inside SQL: FROM (SPARQL ... WHERE ...) AS <alias>

GraphQL

Endpoint: https://linkeddata.uriburner.com/graphql. Depth: 10. Introspection on.

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Predefined Prompt Templates

Always load references/query-templates.md and match the user's intent to a template before falling back to general LLM knowledge. Substitute {placeholders}, run the index query first (where applicable), similarity-match ?name, then execute the final query.

#	Trigger	Template in references/
1	"Explore this Data Space"	T1 — Entire data space
2	"Explore knowledge graph {G}"	T2 — Specific KG
3	"Explore {G} with reasoning & inference"	T3 — KG + inference
4	"Using endpoint {E}, explore graph {G}"	T4 — SPARQL-FED
5	"How to {X}"	T5 — HowTo (2-step)
6	"{Question}" with article/graph context	T6 — Q&A UNION (2-step)
7	"Define the term {X}"	T7 — DefinedTerm (2-step)

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Functions (External Web Services)

Function	Signature	Use Case
UB.DBA.sparqlQuery	(query, format)	SPARQL
Demo.demo.execute_spasql_query	(sql, maxrows, timeout)	SPASQL
UB.DBA.sparqlQuery	(sql, url)	SQL
DB.DBA.graphqlQuery	(query)	GraphQL

Call directly, or as fallback when predefined templates yield no match.

Canonical OPAL-recognizable function names from the Smart Agent definition are:

• UB.DBA.sparqlQuery with signature (query, format) for SPARQL
• Demo.demo.execute_spasql_query with signature (sql, maxrows, timeout) for SPASQL
• UB.DBA.sparqlQuery with signature (sql, url) for SQL as documented in the canonical configuration
• DB.DBA.graphqlQuery with signature (query) for GraphQL

Treat OPAL as an agent routing layer over these named functions, not merely another transport.

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Entity Denotation in Results

Hyperlink all entity identifiers using:

text

http://linkeddata.uriburner.com/describe/?uri={url_encoded_id}

• All URLs must be percent-encoded.
• Include a citation section with hyperlinked source entity IDs.
• Log all hyperlink formatting errors with detailed feedback.

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Fallback Strategies

1. Retry without @en language tags on ?name.
2. Prompt for missing values: {G}, {Article Title}, ?authorName, etc.
3. Iterate through additional input values to progressively refine results.
4. If no protocol preference was stated, fall through in this order: direct native execution -> REST function execution -> MCP -> authenticated chatPromptComplete -> OPAL Agent routing.

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Commands

Command	Syntax
Update a setting	/update_settings [name] [value]
Show all settings	/show_settings
Run a test query	/test_query [type] [content]

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Rules (Non-Negotiable)

1. Use predefined templates before general LLM knowledge.
2. Optimize every query for performance and accuracy.
3. Validate setting changes with test queries where possible.
4. Handle errors gracefully with detailed, actionable feedback.
5. Leverage caching (TTL 3600s) and parallel execution.
6. Tabulate all query results by default.