Lab: Wikidata in RDF - Revision history

Rbo027 at 12:43, 26 February 2024

2024-02-26T12:43:25Z

← Older revision		Revision as of 12:43, 26 February 2024
Line 86:		Line 86:

	'''Task:'''		'''Task:'''
	An earlier task returned labels for all the resource objects, but predicates have labels too. Unfortunately, the wikibase:label SERVICE only provides labels for entities with a ''wd:'' prefix. You must therefore REPLACE all ''wd:'' prefixes of properties with ''~~wdt~~:'' prefixes and BIND the new URI AS a new variable, for example ''?pw''.		An earlier task returned labels for all the resource objects, but predicates have labels too. Unfortunately, the wikibase:label SERVICE only provides labels for entities with a ''wd:'' prefix. You must therefore REPLACE all ''wdt:'' prefixes of properties with ''wd:'' prefixes and BIND the new URI AS a new variable, for example ''?pw''.

	''Tip:'' Use the STR(...) and IRI(...) functions carefully: URIs and prefixes are not strings, and strings are not URIs.		''Tip:'' Use the STR(...) and IRI(...) functions carefully: URIs and prefixes are not strings, and strings are not URIs.

Sinoa at 11:22, 22 February 2024

2024-02-22T11:22:59Z

← Older revision		Revision as of 11:22, 22 February 2024
Line 52:		Line 52:
	Go back to the [http://query.wikidata.org Wikidata Query Service (WDQS)]. (You can run the rest of the lab using a remote SERVICE inside GraphDB, but using WDQS might give you better error messages etc.)		Go back to the [http://query.wikidata.org Wikidata Query Service (WDQS)]. (You can run the rest of the lab using a remote SERVICE inside GraphDB, but using WDQS might give you better error messages etc.)

	Primary Wikidata statements use the prefix ''wd:'' for resources and ''wdt:'' for predicates. Use a FILTER statement to only SELECT ~~''truthy''~~ triples in this sense.		Primary Wikidata statements use the prefix ''wd:'' for resources and ''wdt:'' for predicates. Use a FILTER statement to only SELECT primary triples in this sense.

	These PREFIXes are built into WDQS, but you will need them if you run inside GraphDB:		These PREFIXes are built into WDQS, but you will need them if you run inside GraphDB:

Sinoa at 11:22, 22 February 2024

2024-02-22T11:22:32Z

← Older revision		Revision as of 11:22, 22 February 2024
Line 1:		Line 1:
	==Topics==		==Topics==
	Wikidata in RDF:		Wikidata in RDF:
	* retrieve ~~''truthy''~~ triples about a Wikidata entity		* retrieve primary triples about a Wikidata entity
	* load the semantic data and metadata into GraphDB		* load the semantic data and metadata into GraphDB
	* visualise the semantic data and metadata		* visualise the semantic data and metadata
Line 52:		Line 52:
	Go back to the [http://query.wikidata.org Wikidata Query Service (WDQS)]. (You can run the rest of the lab using a remote SERVICE inside GraphDB, but using WDQS might give you better error messages etc.)		Go back to the [http://query.wikidata.org Wikidata Query Service (WDQS)]. (You can run the rest of the lab using a remote SERVICE inside GraphDB, but using WDQS might give you better error messages etc.)

	~~''Truthy''~~ Wikidata statements use the prefix ''wd:'' for resources and ''wdt:'' for predicates. Use a FILTER statement to only SELECT ''truthy'' triples in this sense.		Primary Wikidata statements use the prefix ''wd:'' for resources and ''wdt:'' for predicates. Use a FILTER statement to only SELECT ''truthy'' triples in this sense.

	These PREFIXes are built into WDQS, but you will need them if you run inside GraphDB:		These PREFIXes are built into WDQS, but you will need them if you run inside GraphDB:
Line 64:		Line 64:

	'''Task:'''		'''Task:'''
	You now have labels for all the resource objects, but you have no ~~truthy~~ triples with literal values. Edit your query (by relaxing the FILTER expression) so it also returns triples where the object has DATATYPE ''xsd:string''.		You now have labels for all the resource objects, but you have no primary triples with literal values. Edit your query (by relaxing the FILTER expression) so it also returns triples where the object has DATATYPE ''xsd:string''.

	'''Task:'''		'''Task:'''
Line 93:		Line 93:

	'''Task:'''		'''Task:'''
	Now you can go back to the SELECT statement that returned ~~''truthy''~~ triples with only resource objects (not literal objects or fingerprints). Extend it so it also includes ~~''truthy''~~ triples "one step out", i.e., triples where the ''subjects'' are ''objects'' of triples involving your reference entity.		Now you can go back to the SELECT statement that returned primary triples with only resource objects (not literal objects or fingerprints). Extend it so it also includes primary triples "one step out", i.e., triples where the ''subjects'' are ''objects'' of triples involving your reference entity.

	In your local GraphDB, use an INSERT statement to add the triples to your local repository. Use ''Explorer'' and ''Graph view'' to visualise the extended graph. You can click on nodes and ''Extend'' them to see their neighbouring nodes.		In your local GraphDB, use an INSERT statement to add the triples to your local repository. Use ''Explorer'' and ''Graph view'' to visualise the extended graph. You can click on nodes and ''Extend'' them to see their neighbouring nodes.

Sinoa: /* Tasks */

2024-02-22T11:16:46Z

Tasks

← Older revision		Revision as of 11:16, 22 February 2024
Line 17:		Line 17:

	''Emergency data:''		''Emergency data:''
	If Wikdata's Query Service is unavailable, you can load [:File:Q42-extended.tar \| this Turtle file] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename the file from ''.tar'' to ''.ttl'' - it is not a ''.tar''-file.)		If Wikdata's Query Service is unavailable, you can load [[:File:Q42-extended.tar \| this Turtle file]] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename the file from ''.tar'' to ''.ttl'' - it is not a ''.tar''-file.)

	'''Task:'''		'''Task:'''

Sinoa at 11:16, 22 February 2024

2024-02-22T11:16:31Z

← Older revision		Revision as of 11:16, 22 February 2024
Line 17:		Line 17:

	''Emergency data:''		''Emergency data:''
	If Wikdata's Query Service is unavailable, you can load [:File:Q42-extended.~~txt~~ \| this Turtle file] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename the file from ''.~~txt~~'' to ''.ttl''.)		If Wikdata's Query Service is unavailable, you can load [:File:Q42-extended.tar \| this Turtle file] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename the file from ''.tar'' to ''.ttl'' - it is not a ''.tar''-file.)

	'''Task:'''		'''Task:'''

Sinoa at 11:12, 22 February 2024

2024-02-22T11:12:46Z

← Older revision		Revision as of 11:12, 22 February 2024
Line 14:		Line 14:
	==Tasks==		==Tasks==
	'''Getting ready:'''		'''Getting ready:'''
	In a web browser, go to [http://query.wikidata.org Wikidata's Query Service (WDQS)]. Be careful to '''always use a limit like LIMIT 100 when you test things'''. Otherwise, you risk being blocked from the query service or, worse, you risk blocking out a whole subdomain.		In a web browser, go to [http://query.wikidata.org Wikidata's Query Service (WDQS)]. Be careful to ''always use a limit like LIMIT 100 when you test things''. Otherwise, you risk being blocked from the query service or, worse, you risk blocking out a whole subdomain.

	'''Emergency data:'''		''Emergency data:''
	If Wikdata's Query Service is unavailable, you can load [:File:Q42-extended.txt \| this Turtle file] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename it from ''.txt'' to ''.ttl''.)		If Wikdata's Query Service is unavailable, you can load [:File:Q42-extended.txt \| this Turtle file] into GraphDB instead, and continue there using ''Q42'' as your example entity. (Remember to rename the file from ''.txt'' to ''.ttl''.)

	'''Task:'''		'''Task:'''
Line 95:		Line 95:
	Now you can go back to the SELECT statement that returned ''truthy'' triples with only resource objects (not literal objects or fingerprints). Extend it so it also includes ''truthy'' triples "one step out", i.e., triples where the ''subjects'' are ''objects'' of triples involving your reference entity.		Now you can go back to the SELECT statement that returned ''truthy'' triples with only resource objects (not literal objects or fingerprints). Extend it so it also includes ''truthy'' triples "one step out", i.e., triples where the ''subjects'' are ''objects'' of triples involving your reference entity.

	In your local GraphDB, use an INSERT statement to add the triples to your local repository. Use ''Explorer'' and ''Graph view'' to visualise the extended graph. You can ~~double-~~click on nodes to see their ~~neighbours~~.		In your local GraphDB, use an INSERT statement to add the triples to your local repository. Use ''Explorer'' and ''Graph view'' to visualise the extended graph. You can click on nodes and ''Extend'' them to see their neighbouring nodes.

Sinoa at 14:40, 21 February 2024

2024-02-21T14:40:53Z

← Older revision		Revision as of 14:40, 21 February 2024
Line 91:		Line 91:

	Afterwards, instead of ''SELECT ?p ?o ?oLabel'', you can write ''SELECT ?p ?pwLabel ?o ?oLabel'' to see the labels for both predicates and resource objects.		Afterwards, instead of ''SELECT ?p ?o ?oLabel'', you can write ''SELECT ?p ?pwLabel ?o ?oLabel'' to see the labels for both predicates and resource objects.

			'''Task:'''
			Now you can go back to the SELECT statement that returned ''truthy'' triples with only resource objects (not literal objects or fingerprints). Extend it so it also includes ''truthy'' triples "one step out", i.e., triples where the ''subjects'' are ''objects'' of triples involving your reference entity.

			In your local GraphDB, use an INSERT statement to add the triples to your local repository. Use ''Explorer'' and ''Graph view'' to visualise the extended graph. You can double-click on nodes to see their neighbours.

Sinoa at 14:37, 21 February 2024

2024-02-21T14:37:04Z

← Older revision		Revision as of 14:37, 21 February 2024
Line 86:		Line 86:

	'''Task:'''		'''Task:'''
			An earlier task returned labels for all the resource objects, but predicates have labels too. Unfortunately, the wikibase:label SERVICE only provides labels for entities with a ''wd:'' prefix. You must therefore REPLACE all ''wd:'' prefixes of properties with ''wdt:'' prefixes and BIND the new URI AS a new variable, for example ''?pw''.

			''Tip:'' Use the STR(...) and IRI(...) functions carefully: URIs and prefixes are not strings, and strings are not URIs.

			Afterwards, instead of ''SELECT ?p ?o ?oLabel'', you can write ''SELECT ?p ?pwLabel ?o ?oLabel'' to see the labels for both predicates and resource objects.

Sinoa: /* If you have more time... */

2024-02-21T14:31:05Z

If you have more time...

← Older revision		Revision as of 14:31, 21 February 2024
Line 84:		Line 84:

	==If you have more time...==		==If you have more time...==

			'''Task:'''

Sinoa at 14:30, 21 February 2024

2024-02-21T14:30:17Z

← Older revision		Revision as of 14:30, 21 February 2024
Line 59:		Line 59:

	'''Task:'''		'''Task:'''
	You have ~~now lost~~ all triples with literal values. Edit your query (by relaxing the FILTER expression) so it also returns triples where the object has DATATYPE ''xsd:string''.		Use Wikidata's in-built ''SERVICE wikibase:label'' to get labels for all the object resources. (Autocompletion with Ctrl-Space will help you set up the service.)

			Afterwards, instead of ''SELECT *'' or ''SELECT ?p ?o'', you can write ''SELECT ?p ?o ?oLabel'' to see the labels for all resource objects.

			'''Task:'''
			You now have labels for all the resource objects, but you have no truthy triples with literal values. Edit your query (by relaxing the FILTER expression) so it also returns triples where the object has DATATYPE ''xsd:string''.

	'''Task:'''		'''Task:'''