Data Model for Storage and Retrieval of Legislative Documents in Digital Libraries Using Linked Data

Abstract

Many countries have provided online access to some types of legislative documents by subject, keywords or date. Nevertheless, the possibility of querying historical versions of the documents is usually an uncommon feature. The dispersion of laws and other legislative documents and their continuous changes make difficult the generation and querying of valid legislative information at a given date. Furthermore, the ripple effect of modifications such as updates, insertions or derogations affecting the entire body of a law or part of it is not always visible for the citizens who are looking for legislative information. Some issues related to change management of legislative documents can be identified: how to apply the history of changes to a version of a legislative document to obtain a new version, and what type of data model might be better to satisfy temporal queries, to store new versions of documents or to obtain them dynamically. The access to all versions of a document and its fragments is important in legislative queries to be sure which law was in force to apply when a case happened. Law documents are produced and stored in information systems with different data models to access and retrieve information about them in a large-scale manner, but most of them do not have law change management functions. Web standards, such as XML, XSLT and RDF, facilitate the separation between content, presentation and metadata, thus contributing to a better annotation and exploitation of information from these documents and their fragments to improve the historical queries and the version generation of legislative documents. This paper presents a proposal of a data model for storage and retrieval of different versions of legislative documents using Linked Data, a method of publishing structured interlinked data, for managing relations between legislative documents and its changes. Document structures, changes to legislation, metadata, requirements of historical queries are analyzed in this work. Furthermore, the proposed model facilitates historical querying of legislative documents and consolidation procedures, allowing update relationships between documents and fragments without changes on the original documents. The model has been tested with Ecuadorian laws, but it could be used for law systems of other countries because the model is independent of the legislative framework.