Mapping management
Introduction
Mappings are declarative rules (expressed in R2RML) which defines the relationship between the underlying data (i.e. table, columns) and the entities in the ontology (i.e. concepts, properties). They are used to create virtualize RDF graphs from SQL databases.
The mapping analysis functionality provides a report to the end-user giving qualitiative indicators regarding some of the well-known mapping challenges.For example global inconsistency and global redundancy checks are implemented. This functionality is fully integrated in the Optique platform’s R2RML editor as shown below.
The mapping management page allows user to import/export mappings, create, rename, edit and delete mappings within the platform itself.
Exercice
1. Once Optique platform is installed (ref. installing Optique), data source setup and ontology create, navigate to the Mappings menu.
2. You may either create a new mapping using the Create button or import existing mapping(s) using the Import button.
3. For editing, simply click on the Mapping name hyperlink in the Collection column.
4. For Analysis, click on the analysis icon as shown below. Report is generated and added to the screen.
Mapping Management screen
5. Optique has an integrated mapping editor, which enables the user to easily create and modify mapping rules. The editor has auto-complete features and analysis tools which guide the user through the process. See below:
Optique mapping editor
6. The SQL query is defined in the “change or extend” link at the top.
7. The mapping itself starts with the Class mapping. Further all properties are added using the “Add Predicate/Object Mapping” link.
8. Preview of resulting triples is a useful tool to lokk into the generated RDF.
Note 1: Ontop module is effectively executing the mapping rules in the most efficient manner.
Note 2: you can bootstrap your data source to generate automatically an ontology and a set of mappings.
