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The purpose of this paper is to compare the use of two Object-Relational models against the use of a post-Relational model for a realistic application. Although real-world applications, in most cases, can be adequately modeled by the Entity-Relationship (ER) model, the transformation to the popular Relational model alters the representation of structures common in reality, like multi-valued and composite fields. Alternative database models have been developed to overcome these shortcomings.

Based on the ER model of a medical application, this paper compares the information representation, manipulation and enforcement of integrity constraints through PostgreSQL and Oracle, against the use of a post-Relational model composed of the Conceptual Universal Database Language (CUDL) and the Conceptual Universal Database Language Abstraction Level (CAL).

The CAL/CUDL pair, although more periphrastic for data definition, is simpler for data insertions, does not require the use of procedural code for data updates, produces clearer output for retrieval of attributes, can accomplish retrieval of rows based on conditions that address composite data with declarative statements and supports data validation for relationships between composite data without the need for procedural code.

To verify, in practice, the conclusions of the paper, complete implementation of a CAL/CUDL system is needed.

The use of the CAL/CUDL pair would advance the productivity of database application development.

This paper highlights the properties of realistic database-applications modelling and management that are desirable by developers and shows that these properties are better satisfied by the CAL/CUDL pair.

The purpose of this paper is to examine personal digital libraries (PDL) as a self-archiving approach, mainly based on individuals’ activities. Literature presents a wide range of perceptions of the term PDL. The rationale of using PDL and the capabilities that PDL should offer are also discussed. The key questions we focus on are: “What are the critical features of PDL?” and “Are there technologies that enable the implementation/incorporation of such capabilities in a low cost software product?”

We focus on “a user centred view of information process”, and examine how PDL could assist individuals to “create, seek, share and manage the life of information” (Foster et al., 2010). The capabilities that PDL should support, and the related technologies, are also discussed. Then, we describe experimentation with a prototype implemented to support/provide the mentioned capabilities. It is used to clarify our view for the creation of PDL. Finally, further discussion and conclusions are presented.

The technology is mature enough for building up PDLs with the specified features/capabilities.

A new perception of the term PDLs is presented. This perception tries to combine the self-archiving approach of information, based on a low-cost tool, and the user-centred approach to manage the “life of information”. This type of library is mainly used to cover personal needs. Users benefit from this type of PDL by personalised handling of information, reduced time to search and seek specific documents in their personal collections and less possibility for broken links or unavailable documents. We must also mention that new opportunities seem to appear for offering PDL as a service in the cloud.