# ontop

> platform to query relational databases as Virtual RDF Knowledge Graphs using SPARQL

**Wikidata**: [Q56861590](https://www.wikidata.org/wiki/Q56861590)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Ontop)  
**Source**: https://4ort.xyz/entity/ontop

## Summary
Ontop is a platform that enables querying relational databases as Virtual RDF Knowledge Graphs using SPARQL. It is an ontology-based data access system that provides a unified view of data from different sources. Ontop is developed by Ontopic, a software company focusing on Virtual Knowledge Graphs.

## Key Facts
- Ontop is a platform to query relational databases as Virtual RDF Knowledge Graphs using SPARQL
- It is an ontology-based data access system that facilitates access to various types of data sources
- Ontop is developed by Ontopic, a software company focusing on Virtual Knowledge Graphs
- It is implemented in Java and licensed under the Apache Software License 2.0
- Ontop has multiple versions, with the latest being 4.0.1 released on August 29, 2020
- It uses SPARQL, GeoSPARQL, and R2RML for querying and data integration
- Ontop is classified as a software framework, free software, server software, and semantic web software

## FAQs
### Q: What is Ontop used for?
A: Ontop is used to query relational databases as Virtual RDF Knowledge Graphs using SPARQL. It enables ontology-based data access, allowing users to access and integrate data from various sources through a unified semantic layer.

### Q: Who developed Ontop?
A: Ontop was developed by Ontopic, a software company specializing in Virtual Knowledge Graphs. The Free University of Bozen-Bolzano is also listed as a developer of Ontop.

### Q: What programming language is Ontop implemented in?
A: Ontop is implemented in Java, an object-oriented programming language. Java was first released in 1995 and has a large community and ecosystem supporting its development.

## Why It Matters
Ontop plays a crucial role in the field of data integration and semantic web technologies. By enabling the querying of relational databases as Virtual RDF Knowledge Graphs using SPARQL, Ontop bridges the gap between traditional relational databases and the semantic web. This allows organizations to leverage their existing data infrastructure while benefiting from the semantic richness and interoperability of RDF and SPARQL. Ontop's ontology-based data access approach simplifies the process of accessing and integrating data from multiple sources, providing a unified view that can be queried using standard semantic web technologies. This is particularly valuable in domains where data is distributed across various systems and needs to be combined for analysis or application development. Ontop's contribution to the semantic web ecosystem is significant, as it enables the practical application of semantic technologies to real-world data integration challenges.

## Notable For
- Enabling querying of relational databases as Virtual RDF Knowledge Graphs using SPARQL
- Providing ontology-based data access to facilitate access to various types of data sources
- Being developed by Ontopic, a company specializing in Virtual Knowledge Graphs
- Supporting multiple versions with continuous development and updates
- Implementing a graphical user interface for user-friendly interaction

## Body
### Development and Versions
Ontop has undergone several major releases since its inception. The platform has evolved through versions 1.13.1 (released September 29, 2014), 1.14 (May 11, 2015), 1.15.0 (October 17, 2015), 1.16.0 (October 17, 2015), 1.17.1 (February 16, 2016), 1.18.0.1 (June 13, 2016), 3.0.0 (August 24, 2019), 3.0.1 (December 9, 2019), 4.0.0 (July 31, 2020), and 4.0.1 (August 29, 2020). This continuous development demonstrates the active maintenance and improvement of the platform.

### Technical Specifications
Ontop is implemented in Java, an object-oriented programming language first released in 1995. The platform uses SPARQL (SPARQL Protocol and RDF Query Language) for querying, GeoSPARQL for geospatial queries, and R2RML (RDB to RDF Mapping Language) for mapping relational databases to RDF. These technologies enable Ontop to provide a powerful and flexible solution for data integration and querying.

### Licensing and Availability
Ontop is licensed under the Apache Software License 2.0, a permissive free software license. This licensing model allows for wide adoption and modification of the software. The source code for Ontop is available on GitHub, promoting transparency and community involvement in its development.

### Applications and Use Cases
Ontop finds applications in various domains where data integration and semantic querying are essential. It is particularly useful in scenarios where organizations need to combine data from multiple relational databases and query them using semantic web technologies. Ontop's ability to create Virtual RDF Knowledge Graphs makes it valuable for knowledge graph applications, data warehousing, and business intelligence systems that require a unified view of distributed data sources.

### Community and Ecosystem
Ontop is part of the broader semantic web and linked data ecosystem. It is related to concepts such as ontology-based data integration, data integration, and knowledge graphs. The platform's development and maintenance involve collaboration between Ontopic, the Free University of Bozen-Bolzano, and the wider open-source community. Ontop's presence on platforms like GitHub and its inclusion in resources like the Social Sciences and Humanities Open Marketplace indicate its recognition and adoption within the research and development community.

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "SoftwareApplication",
  "name": "Ontop",
  "description": "Platform to query relational databases as Virtual RDF Knowledge Graphs using SPARQL",
  "url": "https://ontop-vkg.org",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q55555555",
    "https://en.wikipedia.org/wiki/Ontop"
  ],
  "applicationCategory": "Data Integration",
  "operatingSystem": "Java",
  "license": "Apache Software License 2.0",
  "creator": [
    {
      "@type": "Organization",
      "name": "Ontopic"
    },
    {
      "@type": "CollegeOrUniversity",
      "name": "Free University of Bozen-Bolzano"
    }
  ]
}

## References

1. [Source](https://marketplace.sshopencloud.eu/tool-or-service/SG7WGa)
2. [Release 1.13.1. 2014](https://github.com/ontop/ontop/releases/tag/v1.13.1)
3. [Release 1.14. 2015](https://github.com/ontop/ontop/releases/tag/v1.14)
4. [Release 1.15.0. 2015](https://github.com/ontop/ontop/releases/tag/ontop-1.15.0)
5. [Release 1.16.0. 2015](https://github.com/ontop/ontop/releases/tag/ontop-1.16.0)
6. [Release 1.17.1. 2016](https://github.com/ontop/ontop/releases/tag/ontop-1.17.1)
7. [Release 1.18.0.1. 2016](https://github.com/ontop/ontop/releases/tag/ontop-1.18.0.1)
8. [Release 3.0.0. 2019](https://github.com/ontop/ontop/releases/tag/ontop-3.0.0)
9. [Release 3.0.1. 2019](https://github.com/ontop/ontop/releases/tag/ontop-3.0.1)
10. [Release 4.0.0. 2020](https://github.com/ontop/ontop/releases/tag/ontop-4.0.0)
11. [Release 4.0.1. 2020](https://github.com/ontop/ontop/releases/tag/ontop-4.0.1)
12. [Release 4.0.2. 2020](https://github.com/ontop/ontop/releases/tag/ontop-4.0.2)
13. [Release 4.0.3. 2020](https://github.com/ontop/ontop/releases/tag/ontop-4.0.3)
14. [Release 4.1.0. 2021](https://github.com/ontop/ontop/releases/tag/ontop-4.1.0)
15. [Release 4.1.1. 2021](https://github.com/ontop/ontop/releases/tag/ontop-4.1.1)
16. [Release 4.2.0. 2021](https://github.com/ontop/ontop/releases/tag/ontop-4.2.0)
17. [Release 4.2.1. 2022](https://github.com/ontop/ontop/releases/tag/ontop-4.2.1)
18. [Release 4.2.2. 2022](https://github.com/ontop/ontop/releases/tag/ontop-4.2.2)
19. [Release 5.0.0. 2022](https://github.com/ontop/ontop/releases/tag/ontop-5.0.0)
20. [Release 5.0.1. 2023](https://github.com/ontop/ontop/releases/tag/ontop-5.0.1)
21. [Release 5.0.2. 2023](https://github.com/ontop/ontop/releases/tag/ontop-5.0.2)
22. [Release 5.1.0. 2023](https://github.com/ontop/ontop/releases/tag/ontop-5.1.0)
23. [Release 5.1.1. 2023](https://github.com/ontop/ontop/releases/tag/ontop-5.1.1)
24. [Release 5.1.2. 2024](https://github.com/ontop/ontop/releases/tag/ontop-5.1.2)
25. [Release 5.2.0. 2024](https://github.com/ontop/ontop/releases/tag/ontop-5.2.0)
26. [Release 5.2.1. 2024](https://github.com/ontop/ontop/releases/tag/ontop-5.2.1)
27. [Release 5.3.0. 2025](https://github.com/ontop/ontop/releases/tag/ontop-5.3.0)
28. [Release 5.3.1. 2025](https://github.com/ontop/ontop/releases/tag/ontop-5.3.1)
29. [Release 5.4.0. 2025](https://github.com/ontop/ontop/releases/tag/ontop-5.4.0)
30. [Release 5.5.0. 2026](https://github.com/ontop/ontop/releases/tag/ontop-5.5.0)
31. [Source](https://api.github.com/repos/ontop/ontop)