Virtuoso Tips and Tricks We have a number of tips and tricks articles, covering various areas of Virtuoso functionality. Database Administration How can I specify an OS user name to which the Virtuoso server will switch after opening the listen ports? How can I find out which tables are deadlocking? How can I configure parameters to avoid out of memory errors? How can I control normalization of UNICODE3 accented chars in the free-text index? What should I do if the Virtuoso Server is not responding to HTTP requests? How can I perform a checkpoint against a clustered Virtuoso Server? How can I handle checkpoint condition? How can I backup and restore individual table(s) and individual index(s) on a a new fresh db? How Do I Generate Transient and/or Persistent Linked Data Views atop ODBC or JDBC accessible Relational Data Sources? How Can I perform SQL login with X 509 WebID watermarked certificate? How do I recover from "Invalid log entry in replay" when transaction log is being replayed during server start? How can I move a Virtuoso database from one hardware and/or software platform to another? What should I do if the Virtuoso Server is not responding to HTTP requests? How can I set up Virtuoso Lite Mode? How can I use the LD Meter Utility? How to proxy Virtuoso HTTP server through Apache HTTP server front end? How to configure Virtuoso Cluster slave nodes HTTP listeners? How to configure Virtuoso Elastic Cluster? How to Monitor Virtuoso Memory Consumption? Linux libaio Library not found RDF data management How can I obtain a list of all graphs? How to manage Graph Security Level for SQL Clients? How can I test whether two graphs are equal? How can I add triples to a graph? How can I update triples in a graph? How can I delete triples from a graph? How can I delete triples from a "Large" graph? How Can I Delete Triples containing blank nodes? How can I copy triples from one graph to another? How can I move triples from one graph to another? How can I drop a graph? What is the difference between "DELETE FROM GRAPH" and "CLEAR GRAPH"? How can I drop a graph for which is not clear was it created explicitly or not? How can I perform RDF dumps from Virtuoso Quad store hosted data? How can I perform Dump of RDF Graphs into NQuad dumps? How can I delete graphs using stored procedure? How Can I Delete Triple Patterns that are not scoped to a named graph? What are the differences between create, drop, clear and delete Graph? What are "Generate RDB2RDF triggers" and "Enable Data Syncs with Physical Quad Store" Linked Data Views options? How Can I Diagnose problems associated with Linked Data views generation? How can I display only some information from RDF graph? Can I drop and re-create the DefaultQuadStorage? How can I define a graph with virt:rdf_sponger option set to "on"? How can I configure Sponger to use Asynchronous Query (AQ) threads? How Do I Perform Bulk Loading of RDF Source Files into one or more Graph IRIs? How to exploit RDF Schema and OWL Inference Rules with minimal effort? How the power of OWL based inference enables us exploit the power of Linked Vocabularies? How can I insert binary data to Virtuoso RDF storage in plain queries and with parameter binding via ADO.NET calls? How can I replicate all graphs? How can I insert RDF data from Visual Studio to Virtuoso? How to rename a RDF Graph in the Virtuoso Quad Store? How can I configure Virtuoso for maximum performance with available memory? How can I use the LOAD command to import RDF data? How can I incorporate Content Negotiation into RDF bulk loaders? What free-text options can I use with bif:contains? How can use bif:contains after SPARUL INSERT? How Do I Gecode Data? How I Delete a Specific Triple Across Graphs? How Do I configure Sponger Cartridges? How Do I protect Sponger Endpoint via ACL-s? How do I administer Virtuoso Sponger Instance? How to control user agent usage of Sponger Resources? How Do I use transitive SPARQL query options and Exploit Inference Rules? How Do I use Transitivity via Inference Rules and Transitivity for lists? How Can I Import Linked Data using the Briefcase "Create" feature? What is the ShortenLongURIs Virtuoso configuration parameter? How can I fix RDF Quad Store Index corruption in commercial Release 6.2 and earlier builds How Can I perform Simple Linked Data Deployment using Virtuoso's HTTP Re-write Rules? How Can I Use Virtuoso's Anytime Query Feature? How Can I Split 3.4billion triple UniProt datasets file? How Can I insert triples via Digest Authentication into the Quad Store? How to Update Large SPARQL Data avoiding database checkpoint abortion? How can I Load Data into Virtuoso in Transaction Mode (ie auto commit OFF)? How to convert from Row Store to Column Store Table? How can I determine the time taken to load datasets with RDF Bulk Loader How to create a RDF Graph Replication slave Subscriber node from a master Publisher node SPARQL and SPARUL (SPARQL/Update) What Virtuoso Sponger SPARQL pragmas are supported? Are Custom SPARQL Extension Functions supported and how can I use them? How do I configure Virtuoso to support "wide characters" (e.g., Unicode, UTF-8) for SPARQL querying? How can I optimize SPARQL query performance using bifs (built-in functions)? How can I generate a unique ID via SPARQL? What reification alternatives can I use for Linked Data publishing? Virtuoso Linked Data Deployment In 3 Simple Steps Is there a difference between a "merge" vs "one by one" execution of queries across named graphs? How can I use iSQL to execute SPARQL queries containing the dollar-sign ("$") character? How can I set the quad storage to be included in results of queries made to the SPARQL endpoint? How can I convert between data types using SPARQL in Virtuoso? Is it possible to have the SPARQL endpoint on a different port than the Conductor? How can I manage Date Range SPARQL queries? How to optimize bif:dateadd in SPARQL query using selective index-friendly filter? How do I use SPARUL to change a selection of property values from URI References to Literals? How can I use CONSTRUCT with Prepared Statements? How can I use Expressions inside CONSTRUCT, INSERT and DELETE? How can I use INSERT via CONSTRUCT Statements? How can perform SPARUL Updates without transactional log size getting exceed? How can I get certificate attributes using SPARQL? How does default DESCRIBE mode work? How can I dump arbitrary query result as N-Triples? How do I bind a named graph parameter in a prepared statement? How can I perform Case Insensitive Search across multiple literal values with Virtuoso? What is best method to get a random sample of all triples for a subset of all the resources of a SPARQL endpoint? How can I use SPARQL to make Meshups? How can I get an exact mapping for a date? How can I use SPARUL to add missing triples to a Named Graph How can I use the SPARQL IF operator for SPARQL-BI endpoint? How can I perform search for predicate values? How to clear graphs which are related to empty graphs? How can I enable Dynamic Extended Types (DETs) on a Virtuoso SPARQL Endpoint? How can I use sub-queries to enable literal values based joins? How can I execute query with labels preference order? How can I get object datatype? How to achieve best performance executing a query against SPARQL Endpoint? What methods can I use to protect SPARQL Endpoint? How Do I assign SPARQL role to SQL user? When should I use the function SAMPLE and when GROUP_CONCAT or GROUP_DIGEST? How can I include aggregate function values as objects in SPARQL CONSTRUCT queries? How Do I Clean Up Errant Data using SPARQL Update Language? How to Use SPARQL to add missing isDefinedBy relations to an Ontology? How to Import Ontology? How Can I Use MODIFY to update triples? What are the supported authentication methods associated with a purpose specific default SPARQL endpoint? How Can I execute INSERT/DELETE (SPARUL) statements against a WebID protected SPARQL endpoint? How to expose Linked Data View URIs associated with "References" on a given Table? How Can I perform SPARQL Date Arithmetic calculations? How Can I send SOAP requests to Virtuoso SPARQL Endpoint? How Can I manage Custom Controlling Virtuoso Labels for URI functionality? How Can I Prevent Limits of Sorted LIMIT/OFFSET query? How can I get a full "explain" and "profile" plans for a simple SPARQL query? How Can I Use the core feature of SPARQL logic of pattern matching? How To Let the SPARQL Endpoint Save Results In WebDAV? Where can I find examples for SPARQL 1.1 Features supported in Virtuoso? How Can I use Built-In Functions? How Can I use BIND? How Can I use VALUES? How Can I use Sub-queries? How Can I use NOT EXISTS and MINUS? How Can I use Assignments? How Can I use Property Paths? How Can I use SPARQL Named Graphs with SPARQL 1.1 Property Paths and Reasoning? SPARQL 1.1 Update -- Graph Update: How Can I use INSERT DATA? How Can I use DELETE DATA? How Can I use INSERT/DELETE DATA? How Can I use LOAD? How Can I use CLEAR? How Can I use SPARQL 1.1 INSERT patterns and CONSTRUCT to Enhance Existing Data? SPARQL 1.1 Update -- Graph Management: How Can I use CREATE? How Can I use DROP? How Can I use COPY? How Can I use MOVE? SPARQL 1.1 Graph Store HTTP Protocol: How Can I use HTTP POST, HTTP PUT, HTTP GET and HTTP DELETE? What SPARQL/SPARUL/SPARQL-BI Operations can I perform within Single/Multiple Statements? How Can I use the Virtuoso SPARQL LOAD Service? Where can I find examples for SPARQL Arithmetic Functions supported in Virtuoso? Where can I find examples for Linked Data SPARQL Reference Using the Gene Ontology? How Can I Escape double quotes in entity name? How can I use {is property of} syntax to express inverse relations in Turtle? How can I use the Virtuoso specific query optimizer hint ASSUME? How to discover the capabilities of a SPARQL endpoint en route to enhancing SPARQL-FED usage from Virtuoso instances using LOAD SERVICE ... DATA? How to add SPARQL Endpoint Capabilities Interrogation to Virtuoso SPARQL-FED functionality? How to discover parameters used by SPARQL services that don't support SPARQL-FED? How to handle SPARQL-FED queries for SPARQL endpoints with no OPTION() clause supported? How to split a urlencoded ";-" separated list of urls in a SPARQL query How Can I analyze Linked Open Data with R? How to interrogate attributes of a Virtuoso Server instance via SPARQL How can I run an aggregate like COUNT over multiple columns in SPARQL 1.1? Pivot Viewer and CXML What are Pivot Collections and does Virtuoso support SPARQL CXML? What are the main components of the PivotViewer UI and Collection XML? Does the Virtuoso SPARQL protocol endpoint /sparql supports extensions to the SPARQL standard specifically for CXML? What RDF to CXML Mapping does Virtuoso support? What are the default settings for the CXML generation? Where can I find more details about the Auto-Detection of Facet Type? Configure the Query Timeout setting for the Virtuoso Facet Browser? What are the SparqlCxml Reserved Query Variables? How can I use the virtcxml graph? How can I use Labels in Place of URIs? What are the Link Typing specifics? Where can I find examples for SPARQL CXML Queries? What are the SparqlCxml Deep Zoom Collections for and how can I use them? How can I use the PivotViewer? How can I import CXML? What is the Facet Pivot Bridge? What are DETs and how can I used them for persisting SPARQL Query Results to DAV? What CXML params are supported for the SPARQL URL pattern? How can I change the Facet "Demo Queries" link? How can I change the Facet "/describe" page? Other areas Who Am I How to attach a CSV document to Virtuoso Database Server Instance? How to read Virtuoso Transaction logs? How can I perform Query Optimization Diagnostics? Manage Linked (Open) Data How Can I Use OpenID+WebID? How can I use the WebID Identity Provider Proxy Service? How can I use the WebID Identity Verification Service? How can I use LDAP based WebIDs? How can I use the Virtuoso Mail Verification Service? How can I enable the Virtuoso Entity Framework 3.5 ADO.Net Provider in Visual Studio 2010? How can I write custom crawler using PL? How can I make Multi Thread Virtuoso connection using JDBC? How can I output the result of a SQL SELECT query from isql to a file in Virtuoso? How can I output the results of a SPARQL query run against the /sparql endpoint to a file in Virtuoso? How can I setup Server-side Cross-Origin Resource Sharing (CORS) using Virtuoso? How can I perform Cross-Origin Resource Sharing (CORS) to enable a Virtuoso SPARQL Endpoint? How Can I execute load of sql dump from jdbc? How can I make Recording in Virtuoso? How can I make internal HTTP redirects? Virtuoso Data Center Tips and Tricks Understanding Relationship semantics and reasoning How to Determine Data Usage? How to configure the User Agent Identity used by a Virtuoso Sponger instance? How to Manage SSL Protocols and Ciphers used with Virtuoso? How to extend URIQA DefaultHost value for properly using Facet Browser as search engine? Understanding Virtuoso Timezoneless Datetimes