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1997
In this chapter we describe the Relational Model. This was proposed by Codd, in 1970, long before any relational database system became commercially available. Consequently standards, such as the SQL language, have rapidly emerged in contrast to earlier database systems. The relational model consists of three components: a relation (this being the only
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In this chapter we describe the Relational Model. This was proposed by Codd, in 1970, long before any relational database system became commercially available. Consequently standards, such as the SQL language, have rapidly emerged in contrast to earlier database systems. The relational model consists of three components: a relation (this being the only
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1977
A relation is a mathematical term for a two-dimensional table such as the one shown in figure 3.15. It is characterised by rows and columns, each entry there being a data item value. The reason for calling this a relation rather than a matrix lies in the lack of homogeneity in its entries — the entries are homogeneous in the columns but not in the rows.
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A relation is a mathematical term for a two-dimensional table such as the one shown in figure 3.15. It is characterised by rows and columns, each entry there being a data item value. The reason for calling this a relation rather than a matrix lies in the lack of homogeneity in its entries — the entries are homogeneous in the columns but not in the rows.
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2017
Science can be understood as a vast repository of models. Given a natural system, one may select the models that are most appropriate for whichever purpose one has in mind. Eventually, one can tweak the model as needed. This conception lies at the heart of the Newtonian way of doing science, and it underpins our understanding of science and modeling as
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Science can be understood as a vast repository of models. Given a natural system, one may select the models that are most appropriate for whichever purpose one has in mind. Eventually, one can tweak the model as needed. This conception lies at the heart of the Newtonian way of doing science, and it underpins our understanding of science and modeling as
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ChemInform Abstract: Synthesis of Models Related to Taspine.
ChemInform, 1991AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
SCARPATI, Maria Luisa +2 more
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2011
We developed the modeling relation in the preceding chapter as a relation between a natural system and a formal system. This relation was established through an appropriate encoding of the qualities of the natural system into the propositions of the formal system, in such a way that the inferential structure of the latter correspond to the system laws ...
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We developed the modeling relation in the preceding chapter as a relation between a natural system and a formal system. This relation was established through an appropriate encoding of the qualities of the natural system into the propositions of the formal system, in such a way that the inferential structure of the latter correspond to the system laws ...
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A straightforward formalization of the relational model
Information Systems, 1983There has been a lot of recent interest in the formalization of the relational data model (RDM). Many approaches may be characterized as ones oriented mainly towards declaring the components of the RDM and their interrelationships. Other approaches provide a tool for manipulating the components of RDM so that research topics on the model can be ...
Kalervo Järvelin, Timo Niemi
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2016
In order to gain additional insight into large structure a model is usually built which leaves us with a problem of transfer of parameters between the model and the structure. Problem is addressed on the general level but after discretization and is formulated as a relationship between relevant parameters of the structure and its model.
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In order to gain additional insight into large structure a model is usually built which leaves us with a problem of transfer of parameters between the model and the structure. Problem is addressed on the general level but after discretization and is formulated as a relationship between relevant parameters of the structure and its model.
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1996
The relational data model is unusual in being largely due to the efforts of one man, E. F. Codd. In 1970 E. F. Codd published a seminal paper which laid the foundation for probably the most popular of the contemporary data models. From 1968 to 1988 Codd published more than 30 technical papers on the Relational Data Model. He refers to the total content
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The relational data model is unusual in being largely due to the efforts of one man, E. F. Codd. In 1970 E. F. Codd published a seminal paper which laid the foundation for probably the most popular of the contemporary data models. From 1968 to 1988 Codd published more than 30 technical papers on the Relational Data Model. He refers to the total content
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Injective Models and Disjunctive Relations
Journal of Logic and Computation, 1993The main purpose of this paper is to characterize the nonmonotonic inference relations that can be represented by preferential models in which distinct states never satisfy exactly the same formulae (``injective models''). The key tool is the author's concept of ``preferential orderings''.
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