In this demo, we will show the operation of Ultrawrap Mapper, a semi-automatic software for creating mappings from Relational Databases to RDF in the R2RML language.
In 2012, the W3C ratified two related standards for mapping relational database
contents to RDF: the Direct Mapping [
Recent R2RML editors have been developed which provide users a GUI to create
the mappings [
Ultrawrap Mapper is distinguished Ultrawrap(Mapper( iflnows,evinetreagl rawteasyss;emIti-aeumtobmodaiteisc oantwoloorgky- ODTnoatmorglaoeigtn(y-( SemiBAutoma%c(Mapping( mapping and hides the complexity of tRh2eRsMouLr.ceGdivaetanbaaseJ,DaBnCRc2oRnMneLctifiolne tios RRe2fiRnMeLd(( MRD2aiRrpepMcetLd((( OPSnuottuoarl%ocvege(y(( (internally) automatically created repre- Direct(Mapping(as( sentative of an enhanced Direct Map- Ontology( cpeinssg., TbhoeoDtsitrreacptpMinagpptihneg imsaepnhpianngcedprboy- SPARRQDFL(( Rela%Uolntraalw(Draatpa(base( making it consistent with an ontological model of the source database, the Puta- Fig. 1. Ultrawrap Mapper Architecture tive Ontology.
The Ultrawrap Compiler product is embedded to produce the Putative Ontology.
The Ultrawrap Compiler reads the metadata of the database and, using rule-based
inference, identifies additional semantics beyond the standard direct mapping. Users then
upload a target ontology, (the domain ontology). The third and final step is to create
the mappings. Ultrawrap Mapper incorporates automatic ontology mapping methods to
align the putative and target ontologies [
The output of Ultrawrap Mapper is the mapping between the source relational database and target ontology represented in R2RML. Once the R2RML mapping has been created, any R2RML processor may be used, such as Ultrawrap. Figure 1 depicts the architecture. 2
Step 1: Source Database The developer may choose precisely which tables and attributes of the relation database are to be exposed in the mapping. The tables and attributes that have been checked are the ones that will be part of the mapping process. See Fig 2. Ultrawrap Mapper will read the databases metadata and automatically build an ontological model of the data source; the source putative ontology.
The user may improve the source ontology by incorporating data into the ontology. It is common that data values under an attribute are metadata. For example, in an EMPLOYEE table, an attribute named JOB will have values that may appear in a Job role taxonomy. The user can choose which attributes have these characteristics. Ultrawrap Mapper will make the data values explicit as ontology classes, hence the name Data as a Class. See Fig 3.
Complex data transformations and mappings can be introduced using SQL syntax in the form of view definitions. Ultrawrap Mapper allows users to input SQL queries. For example a view can represent a new concept of Executive Employees which are those who have salary greater than $15000. The result of a query can be previewed in order to verify the result. See Fig 4. Step 2: Target Ontology Any valid OWL ontology or SKOS taxonomy can be uploaded to Ultrawrap Mapper from a file or from the web. If a Target Ontology doesn’t exist, the user can use the OWL representation of the source database as a way to bootstrap the creation of the Target Ontology.
Step 3: Mapping Ultrawrap Mapper bootstraps the editing process by automatically
generating an R2RML file consistent with the enriched version of the direct mapping.
This enriched version reflects Ultrawrap’s inference process that deduces additional
ontological semantics. For each field of the source model the user chooses the
corresponding field in the target model. i.e. this defines a mapping. The actual action is to
replace the default label with a label from the target ontology. Given that Ultrawrap
forms an ontological model of the source relational database, the source putative
ontology, the mapper is able to make mapping recommendations base on aligning the source
and target ontology by using existing ontology matching techniques [
Each row needs to be uniquely identified by a URI. The Template URI field provides a default URI identifier based on the primary key. Users can edit the template URI, if desired. The Preview Mapping button will return the resulting RDF per the chosen mapping. 3
Ultrawrap Mapper is a tool that enables users to create mappings between a relational database and a target ontology without having the conceptual knowledge of R2RML. Additionally, it incorporates semi-automatic ontology matching techniques in order to reduce the burden of creating the mappings. Ultrawrap Mapper is currently being used commercially for relational database integration.