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Actual data set schemas (e.g., 480K classes and 50K properties for DBPedia)
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New!
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Rich data schema library at
viziquer.app (visualization and query environment).
Data schema visualization examples.
Schema showcase available, as well.
Schema extraction and visualization pipeline explained.
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Query environment
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Open viziquer.app.
Register (sign up) as a new user (email checking not done, any e-mail-like string is accepted), then log in.
Create a new project (choose a data schema or give the name for the project).
Further instructions available at Viziquer GitHub wiki.
Create a new diagram, click on the diagram pane. The tabs for classes, properties and individuals shall be to the right.
Double-click an item in a list to seed a query from it.
A short notation and tool explanation with examples in the DBPedia context is available.
A user manual for the classic version explains the query notation and environment concepts.
The query notation presentation over hospital data contains a wealth of query examples.
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Highlights
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A method and library for Visual Data Schemas (Demo at ESWC'2024)
Experience with Visual SPARQL Queries over DBPedia (Presentation and paper at VOILA!'2022)
Towards Visual Queries over Wikidata (Demo at ESWC'2022)
Visual Queries over Distributed Knowledge Graphs (Research project, supported by Latvian Science Council)
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Sample Projects
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The example projects with configurations over Europeana, DBPedia and wikidata can be uploaded from the following locations
(other sample projects are offered during the project initialization, as well):
Europeana sample project.
DBPedia sample project.
Wikidata sample project.
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Contacts
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Contact viziquer@lumii.lv for support, inquiries and any other ViziQuer-related matter.
Team leader e-mail karlis.cerans@lumii.lv
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Open source code
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Check Viziquer repository in GitHub.
The data shape server
serves the schema diagrams and name auto-completion (the actual schema data
are currently stored in Postgres databases).
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Data schema retrieval
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The visual query tool is designed to work with user-specified SPARQL endpoints. The
Schema Extractor
allows for obtaining a JSON-structured schema for a data set.
NB! Use "version 2" within the schema extractor UI.
To use the created schema with ViziQuer/DSS tool, load it into the tool backend database by the
data shape import service tool.
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Data schemas
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The dumps of PostgreSQL databases for data endpoint schema information storing (including, where possible,
the class-property and property-property relations):
Europeana, a sample moderate size schema:
PostgreSQL database for Europeana
Empty schema (can be used to populate with user data):
Empty PostgreSQL database
DBPedia (large, 188 MB): PostgreSQL database for DBPedia (v0)
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Research projects
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Visual Queries in Distributed Knowledge Graphs.
Research project lzp-2021/1-0389, financed by Latvian Science Council.
January 2022 - December 2024
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Core team
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Prof. Kārlis Čerāns (current team leader)
Dr. Lelde Lāce
Jūlija Ovčiņņikova
Mikus Grasmanis
Dr. Agris Šostaks
Dr. Arturs Sproģis
Dr. Uldis Bojārs
We work at Institute of Mathematics and Computer Science, University of Latvia
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Current Research
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K.Cerans, L.Lace, M.Grasmanis, J.Ovcinnikova.
A UML-style Visual Query Environment over DBPedia.
In Proc. of MTSR'2021, Springer Verlag CCIS Series
Download the author manuscript
K.Cerans, J.Ovcinnikova, M.Grasmanis, L.Lace and A.Romane.
Visual Presentation of SPARQL Queries in ViziQuer
In Voila!2021, CEUR Workshop Proceedings, Vol.3023
Čerāns, K., Ovčiņņikova, J., Bojārs, U., Grasmanis, M., Lāce, L. and Romāne, A.,
Schema-Backed Visual Queries over Europeana and Other Linked Data Resources.
ESWC 2021 Satellite Events. Springer LNCS, Vol.12739, pp.82-87.
Download the author manuscript
K.Cerans, A.Sostaks, U.Bojars, J.Ovcinnikova, L.Lace, M.Grasmanis, A.Romane, A.Sprogis and J.Barzdins.
ViziQuer: a Visual Notation for RDF Data Analysis Queries.
In Proc. of MTSR'2018, in Springer Verlag CCIS Series
Download the author manuscript
K.Cerans, A.Sostaks, U.Bojars, J.Ovcinnikova, L.Lace, M.Grasmanis, A.Romane, A.Sprogis and J.Barzdins.
ViziQuer: a Web-based Tool for Visual Diagrammatic Queries over RDF Data
In The Semantic Web: ESWC 2018 Satellite Events, Springer Verlag Lecture Notes in Computer Science, Vol.11155, pp.158-163.
Download the author manuscript
K.Cerans, J.Barzdins, A.Sostaks, J.Ovcinnikova, L.Lace, M.Grasmanis and A.Sprogis.
Extended UML Class Diagram Constructs for Visual SPARQL Queries in ViziQuer/web
In Voila!2017, CEUR Workshop Proceedings, Vol.1947
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Earlier Research
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K.Cerans, J.Ovcinnikova. ViziQuer: Notation and Tool for Data Analysis SPARQL Queries.
In Voila!2016, CEUR Workshop Proceedings, Vol.1704
K.Cerans, J.Ovcinnikova, M. Zviedris. SPARQL Aggregate Queries made easy with Diagrammatic Query Language ViziQuer.
In ISWC 2015 Posters & Demonstrations Track, CEUR Workshop Proceedings, Vol.1486
K.Cerans, J.Ovcinnikova, M. Zviedris. Towards Graphical Query Notation for Semantic Databases. In BIR 2015, Springer LNBIP.
G. Barzdins, S.Rikacovs, M. Zviedris. Graphical Query Language as SPARQL Frontend.
In Local Proceedings of 13th East-European Conference (ADBIS 2009), pp. 93-107. Riga Technical University, Riga. (2009)
G.Barzdins, E.Liepins, M.Veilande, M.Zviedris, "Ontology Enabled Graphical Database Query Tool for End-Users",
Selected papers from DBIS'2008, Hele-Mai Haav (Eds.), Frontiers in Artificial Intelligence and Applicatons series, IOS Press, 2009. 187:105-116
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