Much of relational algebra and the underlying principles of relational database design have a simple representation in the theory of domains that is traditionally used in the denotational semantics of programming languages. By investigating the possible orderings on powerdomains that are well-known in the study of nondeterminism and concurrency it is possible to show that many of the ideas in relational databases apply to structures that are much more general than relations. This also suggests a method of representing database objects as typed objects in programming languages. In this paper we show how operations such as natural join and projection -- which are fundamental to relational database design -- can be generalized, and we use this generalized framework to give characterizations of several relational database concepts including functional dependencies and universal relations. All of these have a simple-minded semantics in terms of the underlying domains, which can be thought ...

An equational language to specify object-oriented conceptual models is defined. Objects are considered to be characterized by a unique object identifier and have static and dynamic structure. Examples of static structure are classification, aggregation, generalization and grouping, examples of dynamic structure are events, processes, local (intra-object) and global (inter-object) and communication. The language, called CMSL, has a declarative (algebraic) semantics, which is divided into two. The part of CMSL that can be used to specify static structures has an initial algebra semantics, in which the data elements are object versions. The part dealing with process has a larger algebra as semantics; in this paper we use an algebra of graphs modulo bisimulation equivalence. About both models can be reasoned using standard equational logic. Apart from the combination of static and dynamic features of objects in an algebraic framework, and the joint specification of this in an equational la...

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. In this paper, we present both the theoretical framework and a prototype of a query processing facility that supports the exploration and query of databases from a mobile computer based on the manipulation of icons. Icons are particularly suitable for mobile computing since they can be manipulated without typing. The facility requires no special knowledge of the location or the content of the remote database nor understanding of the details of the database schema. Its iconic query language involves no path specification in composing a query. The query facility provides metaquery tools that assist in the formulation of complete queries in an incremental manner on the mobile computer and without involving access to the actual data in the remote database. By not requiring constant access and caching of the actual data, it is able to effectively cope with the inherent limitations in memory and battery life on the mobile computer, disconnections and restricted communication bandwidth, and...

This paper discusses several mechanisms for creating relations out of XML documents. A relation generator consists of two parts: (1) a tuple of path expressions and (2) an index indicating which path expressions may not be assigned the null value. Evaluating a relation generator involves nding tuples of nodes that satisfy the path expressions and are related to one another in a meaningful fashion. Dierent semantics for evaluation are given that take into account the possible presence of incomplete information. The complexity of generating relations from documents is analyzed and evaluation algorithms are described.

This paper gives a data structure (UDS) for supporting database retrieval, inference and machine learning that attempts to unify and extend previous work in relational databases, semantic networks, conceptual graphs, RETE, neural networks and case-based reasoning. Foundational to this view is that all data can be viewed as a primitive set of objects and mathematical relations (as sets of tuples) over those objects. The data is stored in three partially-ordered hierarchies: a node hierarchy, a relation hierarchy, and a conceptual graphs hierarchy. All three hierarchies can be stored as "levels" in the conceptual graphs hierarchy. These multiple hierarchies support multiple views of the data with advantages over any of the individual methods. In particular, conceptual graphs are stored in a relation-based compact form that facilitates matching. UDS is currently being implemented in the Peirce conceptual graphs workbench and is being used as a domain-independent monitor for state-space search domains at a level that is faster than previous implementations designed specifically for those domains.In addition it provides a useful environment for pattern-based machine learning.

In this paper, we consider the problems of transforming UML models into object-relational databases, which consist of static aspects and dynamic aspects. For the static aspects of the database, we first remove semantically overloaded elements, and then our algorithms generate Nested Normal Form nested tables. For the dynamic aspects of the database, we show how to map statechart diagrams into triggers. We begin our analysis of a statechart that potentially leads to nontermination of execution. We pay attention to the events, conditions, and actions of the transitions of states in the given statechart. Further, we investigate the properties of confluence and observable determinism of the generated triggers.

In this paper, we consider the problems of transforming UML models into object-relational databases, which consist of static aspects and dynamic aspects. For the static aspects of the database, we first remove semantically overloaded elements, and then our algorithms generate Nested Normal Form nested tables. For the dynamic aspects of the database, we show how to map statechart diagrams into triggers. We begin our analysis of a statechart that potentially leads to nontermination of execution. We pay attention to the events, conditions, and actions of the transitions of states in the given statechart. Further, we investigate the properties of confluence and observable determinism of the generated triggers. 1.