Explanation of jargon and technical terms
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Glossary - Technical Terms and Jargon explained

Dictionary

In the context of mapping, dictionaries are a common pattern for deciding the class of an entity depending on the values in a database column. The support built into Ontopic Studio for this pattern simplifies the use of the pattern reducing mistypings and misalignments between values and classes.


Mentioned in: Map column values to classes in your Knowledge Graph without the usual pain
Entity

A node in the Knowledge Graph. An entity is typically identified by an IRI.


Wikidata: Q35120
Mentioned in: Mapping a database table to a class Why using mappings for building a Knowledge Graph
Foreign Key

A column (or collection of columns) that refers to the primary key (non-nullable uniquely identified values) in another table. It acts as a cross-reference between tables. A foreign key always must refer to a primary key somewhere.


Wikidata: Q1056760
Mentioned in: Mapping many-to-many relationships to object properties
IRI

The Internationalized Resource Identifier identifies a logical or physical resource used by web technologies. Example: http://data.mycompany.com/employee/1234.


Wikidata: Q424583
Mentioned in: Mapping database columns to data properties Mapping many-to-many relationships to object properties
Lens

In Ontopic Studio, a lens is a logical view over the original database table, which allows to visualize and edit the content without altering the original data stored in the data source.


Mentioned in: Mapping a database table to a class Mapping database columns to data properties Mapping many-to-many relationships to object properties Map column values to classes in your Knowledge Graph without the usual pain
Mapping

In the case of a relational data source, a (schema) mapping connects tables and columns from the source to the components of the semantic layer, which for a Knowledge Graph are classes and properties. A common standard language for mapping relational databases to RDF graphs is R2RML, but other languages exist. A mapping is composed of single mapping entries.


Mentioned in: Why using mappings for building a Knowledge Graph Mapping database columns to data properties
Mapping Entry

A mapping entry is the detailed rule descrbing how to create a particular part of the Knowledge Graph from a well defined part of the data source.


Mentioned in: Why using mappings for building a Knowledge Graph Mapping database columns to data properties A Quickstart Guide to Ontopic Studio
Materialization

The creation of RDF triples in the Knowledge Graph. In this context, it is typically data from relational databases, from CSV files or spreadsheet files being transformed to RDF triples and stored in specialized graph databases, also called triple stores.


Wikidata: Q1127410
Mentioned in: Mapping many-to-many relationships to object properties
OBDA Mapping Format

Ontop can build Virtual Knowledge Graphs as described by R2RML mappings or in the custom OBDA file format. Both files formatsare equivalent, as far as expressivity is concerned. OBDA file format is preferred by many practitioners, being perceived as easier to read.


Mentioned in: How to deploy your Knowledge Graph in a graph database with Ontop
Ontop

Ontop translates queries from SPARQL, the query language used for RDF graphs, into SQL, the query language for traditional databases. Data from relational (traditional) databases appears therefore as a Knowlegde Graph, but without the need to copy and transform data from a relational database into a specialized graph database. This is then called a virtual knowledge graph. Ontop also allows to transform batch-wise whole database tables, as well as entire databases, to RDF graphs. This modality is then called materialization. Ontop is Open Source software and is been developed by several universities and companies. Ontopic provides commercial support and services for Ontop.


Wikidata: Q56861590
Mentioned in: Why using mappings for building a Knowledge Graph
Ontology

In the context of Knowledge Graphs, an ontology defines classes and properties, as well the relationships between them and is used to provide a struture to data. Ontologies can also be used for automatic reasoning.


Wikidata: Q324254
Mentioned in: Map column values to classes in your Knowledge Graph without the usual pain
R2RML

Mappings from relational databases to RDF datasets can be expressed in terms of the R2RML mapping language. R2RML is a W3C standard.


Wikidata: Q109734057
Mentioned in: Why using mappings for building a Knowledge Graph Some facts to consider when choosing a Mapping Editor
SPARQL

SPARQL is a language for querying RDF datasets. It is deliberately similar to SQL, but adapted to query graphs, whereas SQL is designed for querzing relational databases. SPARQL is a W3C standard.


Wikidata: Q54871
Mentioned in: What is a Virtual Knowledge Graph (VKG), and what are its applications for business?
SPARQL Endpoint

A SPARQL endpoint is characterized by a process, typically associated with a database, able to understand SPARQL queries, either returning the requested data or modyfying the data, as specified in the query. SPARQL endpoints use the HTTP protocol for communication and each endpoint has a defined URL.


Wikidata: Q26261192
Mentioned in: How to deploy your Knowledge Graph in a graph database with Ontop
Template

A template is used to generate subject IRIs for entities. Example: http://data.mycompany.com/employee/{empno}, where {empno} will be substituted with a unique key in order to create unique IRIs.


Mentioned in: Mapping a database table to a class Mapping many-to-many relationships to object properties Map column values to classes in your Knowledge Graph without the usual pain
Virtual Knowledge Graph (VKG)

SPARQL query answering does not involve any materialization in RDF. Instead SPARQL queries are translated to SQL queries, which are then executed over the data sources.One of the most used and advanced Virtual Knowledge Graph engines is Ontop.


Wikidata: Q55118556
Mentioned in: Why using mappings for building a Knowledge Graph Mapping many-to-many relationships to object properties