Library Digital Resources: Relational Databases or Catalogues? (A Short Tutorial)

With the rush to deploy Information Technology in all service areas, there is tremendous pressure on small and medium size (around 1 lakh holdings) libraries in India to digitize their records. In doing so, Librarians wishing to go digital face the risk of opting for platforms and back-ends not truly designed for managing library records. The fact that designers of almost all Library Management Systems currently popular, have opted for the Relational Database model in structuring library data, further confounds the Librarian's choice and almost always leads to the deployment of inappropriate tools. This article (tutorial) argues that Library records cannot be conveniently cast in the conventional RDBMS framework without significant modifications to the structures of Library data as librarians have conventionally structured it, as well as key concepts in conventional RDBMS. It is the premise of this article that these modifications can be made only at the risk of seriously detracting from the effectiveness of the tools as well as the quality of the data. The premise here is that Library data are not relational databases but catalogs in the sense that they cannot be normalized to fit the canonical normal forms. An alternative framework of tools (WWWISIS back-end from the ISIS family) and structured data (ISO 8059) is suggested and explained

Models of sharing graphs: a categorical semantics of let and letrec

To my parents A general abstract theory for computation involving shared resources is presented. We develop the models of sharing graphs, also known as term graphs, in terms of both syntax and semantics. According to the complexity of the permitted form of sharing, we consider four situations of sharing graphs. The simplest is first-order acyclic sharing graphs represented by let-syntax, and others are extensions with higher-order constructs (lambda calculi) and/or cyclic sharing (recursive letrec binding). For each of four settings, we provide the equational theory for representing the sharing graphs, and identify the class of categorical models which are shown to be sound and complete for the theory. The emphasis is put on the algebraic nature of sharing graphs, which leads us to the semantic account of them. We describe the models in terms of the notions of symmetric monoidal categories and functors, additionally with symmetric monoidal adjunctions and trace