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Semantic database modeling: Survey, applications, and research issues
 ACM Computing Surveys
, 1987
"... Most common database management systems represent information in a simple recordbased format. Semantic modeling provides richer data structuring capabilities for database applications. In particular, research in this area has articulated a number of constructs that provide mechanisms for representi ..."
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Cited by 240 (3 self)
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Most common database management systems represent information in a simple recordbased format. Semantic modeling provides richer data structuring capabilities for database applications. In particular, research in this area has articulated a number of constructs that provide mechanisms for representing structurally complex interrelations among data typically arising in commercial applications. In general terms, semantic modeling complements work on knowledge representation (in artificial intelligence) and on the new generation of database models based on the objectoriented paradigm of programming languages. This paper presents an indepth discussion of semantic data modeling. It reviews the philosophical motivations of semantic models, including the need for highlevel modeling abstractions and the reduction of semantic overloading of data type constructors. It then provides a tutorial introduction to the primary components of semantic models, which are the explicit representation of objects, attributes of and relationships among objects, type constructors for building complex types, ISA relationships, and derived schema components. Next, a survey of the prominent semantic models in the literature is presented. Further, since a broad area of research has developed around semantic modeling, a number of related topics based on these models are discussed, including data languages, graphical interfaces, theoretical investigations, and physical implementation strategies.
Schema Equivalence in Heterogeneous Systems: Bridging Theory and Practice
, 1993
"... Current theoretical work offers measures of schema equivalence based on the information capacity of schemas. This work is based on the existence of abstract functions satisfying various restrictions between the sets of all instances of two schemas. In considering schemas that arise in practice, howe ..."
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Cited by 67 (2 self)
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Current theoretical work offers measures of schema equivalence based on the information capacity of schemas. This work is based on the existence of abstract functions satisfying various restrictions between the sets of all instances of two schemas. In considering schemas that arise in practice, however, it is not clear how to reason about the existence of such abstract functions. Further, these notions of equivalence tend to be too liberal in that schemas are often considered equivalent when a practitioner would consider them to be different. As a result, practical integration methodologies have not utilized this theoretical foundation and most of them have relied on adhoc approaches. We present results that seek to bridge this gap. First, we consider the problem of deciding information capacity equivalence and dominance of schemas that occur in practice, i.e., those that can express inheritance and simple integrity constraints. We show that this problem is undecidable. This undecidab...
Schema Intension Graphs: A Formal Model for the Study of Schema Equivalence
, 1993
"... We develop a formal data model, the Schema Intension Graph (SIG) model, to aid in understanding the relative information capacity of schemas containing constraints. The basic building blocks of the SIG model are sets that may be combined by the nested application of union and product constructors. T ..."
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Cited by 5 (1 self)
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We develop a formal data model, the Schema Intension Graph (SIG) model, to aid in understanding the relative information capacity of schemas containing constraints. The basic building blocks of the SIG model are sets that may be combined by the nested application of union and product constructors. The model also permits the expression of binary relations on sets and simple integrity constraints on these relations. We discuss the motivation used in designing the model and establish some fundamental results on the model. We consider the problem of constraint implication in the SIG model and give a sound and complete set of implication rules for a subclass of SIG schemas, called simple SIG schemas. The general constraint implication problem is shown to be undecidable. Finally, we consider information capacity preserving translations of a subclass of relational schemas with functional and inclusion dependencies into simple SIG schemas. These translations assist in determining the relative ...
§1. Problem of Algebra Lecture 0 Page 1 Lecture 0
"... This lecture is an orientation on the central problems that concern us. Specifically, we identify three families of “Fundamental Problems ” in algorithmic algebra (§1 –§3). In the rest of the lecture (§4– §9), we briefly discuss the complexitytheoretic background. §10 collects some common mathemati ..."
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This lecture is an orientation on the central problems that concern us. Specifically, we identify three families of “Fundamental Problems ” in algorithmic algebra (§1 –§3). In the rest of the lecture (§4– §9), we briefly discuss the complexitytheoretic background. §10 collects some common mathematical terminology while §11 introduces computer algebra systems. The reader may prefer to skip §411
Relstlve Information Cspaclty of Simple Relational Database Schemats* (Extended Abstract)
"... Fundamental notions of re1ativ.e. information capacity between database structures are studied in the context of the relational model. Four progressively less restrictive formal definitions of ‘dominance ’ between ..."
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Fundamental notions of re1ativ.e. information capacity between database structures are studied in the context of the relational model. Four progressively less restrictive formal definitions of ‘dominance ’ between