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Data model

The data contained in the bibliographic and author records have to be arranged according a model that specifies their basic composite units (entities), their characteristics or attributes (properties) and the relationships established between them.

In order to represent the resources in RDF format, ontologies have been used, or models that have been agreed by the library community and put forward by IFLA, the International Federation of Library Associations. The data from the Biblioteca Nacional de España catalogue have been modelled in accordance with the entities and links described in the FRBR model published by IFLA in 1999. This model comprises a theoretical frame of reference for bibliographic catalogues and their relationship with users' needs. This model lists all the entities that appear in the bibliographic world, their properties and the relationships between them:

FRBR 

Figure 1. A basic diagram of FRBR entities and primary relationships

 

FRBR has been used as a conceptual reference model and a data model. It provides a full and ordered description of the bibliographic world, making it possible to group common objects and express the relationships between them, so they can be linked with other theoretical models in other similar disciplines.

Figure 2. Conceptual diagram of the use of the IFLA models
Figure 2. Conceptual diagram of the use of the IFLA models

 

The entities, relationships and properties of these ontologies have been published by IFLA in RDF format on the OMR (Open Metadata Registry) and have been approved and acknowledged by W3C as valid Semantic Web standards. In parallel, the labels of these classes and properties were translated into Spanish in collaboration with IFLA. (http://metadataregistry.org/schemaprop/list/schema_id/5.html)

The bibliographic descriptions themselves had to comply with the ISBD (International Standard for Bibliographic Description) model and attributes, which are set out in RDF format in http://metadataregistry.org/schemaprop/list/schema_id/25.html.

However, in order to ensure greater control of the vocabulary used in the description of objects, a BNE-specific ontology, connected with all these vocabularies, has been used for this new version of datos.bne.es. Aside from FRBR and ISBD properties, other properties from other vocabularies have been used for reference, such as RDA, Dublin Core and Bibo, and in some cases single properties have been described within the ontology.

MARC21 authority files and bibliographic records have been mapped using ontological properties. Various mapping initiatives have been undertaken:

  • Mapping for each field and combination of sub-fields to determine the FRBR entity (Person, Corporate Entity, Work, Subject). This mapping has been undertaken on the authority files.
  • Mapping to establish the links between entities, using the variations in the combination of field/sub-fields between two authority files and between one authority file and a bibliographic record.
  • Mapping of each field/ sub-field combination, both of bibliographic records and authority fields, using ontological properties