Isabella Merlo

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Although many temporal extensions of the relational data model have been proposed, there is no comparable amount of work in the context of object-oriented data models. Moreover, extensions to the relational model have been proposed in the framework of SQL standards, whereas no attempts have been made to extend the standard for objectoriented databases,(More)
In this paper we investigate some issues arising from the introduction of multiple temporal granularities in an objectoriented data model. Although issues concerning temporal granularities have been investigated in the context of temporal relational database systems, no comparable amount of work has been done in the context of object-oriented models.(More)
Several advanced applications, such as those dealing with the Web, need to handle data whose structure is not known a-priori. Such requirement severely limits the applicability of traditional database techniques, that are based on the fact that the structure of data (e.g. the database schema) is known before data are entered into the database. Moreover, in(More)
Managing and querying information with varying temporal granularities is an important problem in databases. Although there is a substantial body of work on temporal granularities for the relational data model [11], a comprehensive framework is lacking for the object-oriented paradigm. To the best of our knowledge, a formal treatment of temporal queries with(More)
| An active database is a database in which some operations are automatically executed when speciied events happen and particular conditions are met. Several systems supporting active rules in an object-oriented data model have been proposed. However, several issues related to the integration of triggers with object-oriented modeling concepts have not been(More)
Managing and relating temporal information at different time units is an important issue in many applications and research areas, among them temporal object-oriented databases. Due to the semantic richness of the objectoriented data model, the introduction of multiple temporal granularities in such a model poses several interesting issues. In particular,(More)
We extend the standard for object-oriented databases, ODMG, with reactive features, by proposing a language for specifying triggers and defining its semantics. This extension has several implications, thus we make three different specific contributions. First, the definition of a declarative data manipulation language for ODMG, which is missing in the(More)