Roberto V. Zicari

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The problem of translating view updates to database updates is considered. Both databases and views are modeled as data abstractions. A data abstraction consists of a set of states and of a set of primitive update operators representing state transition functions. It is shown how complex update programs can be built from primitive update operators and how(More)
LOGRES is a new project for the development of extended database systems which is based on the integration of the object-oriented data modelling paradigm and of the rule-based approach for the specification of queries and updates. The data model supports generalization hierarchies and object sharing, the rule-based language extends <italic>Datalog</italic>(More)
We describe a data model for structured office information objects, which we generically call &#8220;documents,&#8221; and a practically useful algebraic language for the retrieval and manipulation of such objects. Documents are viewed as hierarchical structures; their layout (presentation) aspect is to be treated separately. The syntax and semantics of the(More)
Current object database management systems support user-defined conversion functions to update the database once the schema has been modified. Two main strategies are possible when implementing such database conversion functions: immediate or lasy database updates. In this paper, we concentrate our attention to the definition of implementation strategies(More)
The object-oriented data model TM is a language that is based on the formal theory of FM, a typed language with object-oriented features such as attributes and methods in the presence of subtyping. The general (typed) set constructs of FM allow one to deal with (database) constraints in TM. The paper describes the theory of FM, and discusses the role that(More)
Abstract--Multitasking is one of the most novel aspects of Ada. However, the combination of language primitives for concurrent execution of tasks, synchronization, termination, abortion, exception handling, etc. make Ada programs difficult to understand and analyze. This is partly due to the inherent complexity of the language and partly to the lack of a(More)