J. T. Teorey. Database Modeling and Design: The EntityRelationship Approach. Morgan Kaufmann, Los Altos, 1989.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....conceptual (ER ) schema design and second, translation into a relational schema. Conceptual models richer than the relational model provide a more precise and higher level description of data requirements and constitute the starting point for logical design. Several methods have been proposed [12, 14, 19, 26] for # This work is part of the YEROOS (Yet another project on Evaluation and Research on Object Oriented Strategies) project, principally based at the University of Louvain. See http: yeroos.qant.ucl.ac.be University of Louvain, IAG QANT, 1 Place des Doyens, 1348 Louvain La Neuve, Belgium, ....

....methods that remove anomalies due to cycles and inclusion constraints. We propose an integrated design method including normalization into IN NF based on [Goh92] These algorithms comprise three main steps. The following sections develop these steps : 1) ER to Relational Mapping (see also [12, 14, 19, 26, 28]) an ER schema is mapped into a set of non normalized relations. Data dependencies are generated to represent implicit constraints of the ER schema. 2) Relation normalization and key generation: each relation is decomposed into a set of 3NF relations and at least one key is found for each 3NF ....

T. Teorey. Database Modeling and Design: The Entity-Relationship Approach. Morgan Kaufmann, 1990.

....conceptual (ER ) schema design and second, translation into a relational schema. Conceptual models richer than the relational model provide a more precise and higher level description of data requirements and constitute the starting point for logical design. Several methods have been proposed [12, 14, 19, 26] for ER to relational translations but the semantic distance between the two models can lead to anomalies in the logical schema. # This work is part of the YEROOS (Yet another project on Evaluation and Research on Object Oriented Strategies) project, principally based at the University of ....

....Hence, the interest of enhanced ER based design methods removing anomalies due to cycles and inclusion constraints. We propose an integrated design method including normalization into IN NF based on [Goh92] These algorithms comprise three main steps: 1) ER to Relational Mapping (see also [12, 14, 19, 26, 28]) an ER schema is mapped into a set of nonnormalized relations. Data dependencies are generated to represent implicit constraints of the ER schema. 2) Relation normalization and key generation: each relation is decomposed into a set of 3NF relations and at least one key is found for each 3NF ....

T. Teorey. Database Modeling and Design: The Entity-Relationship Approach. Morgan Kaufmann, 1990.

....these inconsistencies become very costly to correct, so early discovery of an error is highly desirable. Direct treatment of structural validity as a concept is rare in the literature. Some unary structural validity rules are partly discussed in other publications, such as [14] 1] 8] and [13], but they don t exhaustively cover all the combinations of maximum and minimum cardinality and are usually confined to making buttress points concerning other issues. Structural validity in the literature is almost always treated as a property of a study; in this paper we treat it as the ....

Teorey, Toby J., Database Modeling and Design - The Entity-Relationship Approach, Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1994.

....presentation we must briefly define some terminologies that are key to the environment supporting redundancy. A data model can be represented by a diagram of entities interconnected by relationships. This connectivity represents the mapping of the associated entities instances in the relationship [TEOR94]. Teorey uses rectangles to represent entities connected by straight lines to diamonds representing relationships. The maximum cardinality constraint is indicated by the fill of the diamond (see Figure 1) Minimum cardinality is represented by an open circle placed on the line between the entity ....

Teorey, Toby J., 1994. Database Modeling and Design - The Entity-Relationship Approach , Morgan Kaufmann Publishers, Inc., San Mateo, CA.

....the validity of an ER diagram containing paths with binary and ternary relationships. Ternary relationships are associations involving three entities. In a ternary relationship the association of an instance from each entity participating in the relationship is represented as a triple [ELMA94] [TEOR94]. Membership in the triple implies that instance pairs of two entities is associated with an instance from the remaining entity. Consider the example of a ternary relationship with entities X, Y, and Z, each containing one instance X1, Y1, and Z1, respectively. The triple represents the ....

Teorey, Toby J., 1994. Database Modeling and Design - The Entity-Relationship Approach, Morgan Kaufmann Publishers, Inc., San Mateo, CA.

....organizational processes. Definition 4. 1: An EAM subsystem is an abstraction which expresses inter objects statics and dynamics, i.e. the subsystem schema is an ERC subschema satisfying one or more standard cohesion criteria, i.e. dominance, abstraction, relationship and view grouping [22, 12]; the subsystem dynamics is expressed by a set of processes describing the interaction among subsystem components. These processes satisfy dynamic cohesion criteria and read and modify only the subsystem schema. The subsystem is called elementary if its schema is an elementary subschema. ....

....on this purpose the ERC schema describing the IS structure and the description of IS processes. Subsystems identification is guided by the decomposition of the IS processes. At each step, we associate to a subprocess the subschema of interest, where subschema must satisfy static cohesion criteria [22, 12]; the result is a candidate subsystem. The set of candidate subsystems is analyzed to find subsystems relevant to the IS, and, at the same time to update the IS global schema by possibly introducing new entity and or relationship types. In top down IS specification we use the notion of refinement ....

T.J. Teorey, Database Modeling and Design - The Entity-Relationship Approach, Morgan Kaufmann Publishers, 1990

....to their inputs. 1 DDEW was supported by Rome Air Development Center, USAF, under Contract F30602 83 C0073 to Computer Corporation of America (CCA) CCA s Advanced Information Technology Division is now Xerox Advanced Information Technology. 2 A slight variant of this notation was adopted in [TEOR90]. As formalized below, the information content (or capacity) of a schema is defined by the set of legal states of the database. Two schemas are called content equivalent if there is an invertible (total, onto, 1:1, and attributepreserving [HULL84] mapping between their possible ....

T. Teorey, Database Modeling and Design: The Entity-Relationship Approach, Morgan Kaufmann,

....specific examples taken from the Genesis and Avoca prototypes. 4.1 Layered Software Designs and Transformations Object Oriented Designs. A primary result of an object oriented design is an object model or schema that defines the classes of objects of an application and their interrelationships [Boo91, Rum91, Teo90]. Associated with each class is the set of operations that can be performed on its objects, plus the set of object attributes. Object models are depicted by class diagrams, where classes are nodes and edges are relationships. We draw class diagrams as ER diagrams, although any comparable notation ....

T.J. Teorey, Database Modeling and Design: The Entity-Relationship Approach, Morgan-Kaufmann, 1990.

....event modeling. The domain of manufacturing equipment requires a mix of all three dimensions. However, since this study is at the beginning stage of modeling this domain 12 , it is oriented toward data modeling the dimension least dependent on applications. Entity Relationship (ER) Diagrams [50] are used to represent entity classes and their inter relationships. These diagrams have been extended with other modeling notation to suit the domain. Relationships shown are mostly aggregation or inheritance. In some cases it was convenient to identify the entities in a tabular form. In most ....

T. J. Teorey, Database Modeling and Design: The EntityRelationship Approach, Morgan Kaufmann Publishers, Inc., San Mateo, California, 1990.

....earlier, there is a similarity between C nested classes and P components. In terms of expressiveness, both constructs are roughly equivalent. However, the basic difference arises from their intended usage. Nested classes do not arise in popular object oriented design methodologies (e.g. [Boo91, Rum91, Teo90]) their intended use in C is to facilitate the implementation of the enclosing class. In contrast, a basic tenet of GenVoca is to identify groups of interrelated classes and encapsulate them within component constructs. In short, P components encapsulate subsystems (i.e. multiple classes) ....

T. J. Teorey. Database Modeling and Design: The Entity-Relationship Approach. MorganKaufmann, 1990.

....caution in this context, since only few data models possess proper formal mathematical semantics, such as Chen s Entity Relationship model [Che76] TAXIS [MW80, NCL 87] IFO [AH87] or the algebraic approach of [SSE87] for example. The well tried and widely accepted Entity Relationship model [Teo90, BCN92] is often considered to be the most appropriate data model, since it captures most of the important phenomena of the real world and expresses them in a natural and easily understandable way. Many experts use the Entity Relationship model in their daily work. Nevertheless, a number of ....

T.J. Teorey. Database Modeling and Design -- The Entity-Relationship Approach. Morgan Kaufmann, San Mateo (CA), 1990.

....structural and dynamic modeling. 1 Introduction Proc. 12th Int. Conf. on Entity Relationship Approach (ER 93) R. Elmasri, V. Kouramajian, B. Thalheim (Eds. Springer, Berlin, LNCS 823, pp. 376 389 (1994) Nowadays the Entity Relationship approach [Che76] has been accepted as a quasi standard [Teo90, BCN92] for the conceptual design of databases and information systems. This approach is undoubtedly a very popular tool for bridging the gap between database designers and users of database systems. One issue in favor of Entity Relationship design is based on the fact that the graphical ....

T.J. Teorey. Database Modeling and Design -- The Entity-Relationship Approach. Morgan Kaufmann, San Mateo (CA), 1990.

....as in the HERM approach. A student can enroll a course given by a professor in a certain room only if this course information is kept in the lecture relationship set. It is surprising that translating this scheme leads to a relational scheme which is not minimal. Using the translation theory of [Teo89] we obtain the following two relation schemes: LECTURE = f Professor .Person s number, Course.CNu, Room.Nr, Room.Building, fi HERM Foundations 16 Time(Day,Hour) Semester.Year, Semester.Season g, f Professor .Person s number, Course.CNu, Semester.Year, Semester.Season g ) ENROLL = ....

....comp(R; E 2 ) 2 f(l; kjl 2 f0; 1g; l k; k 1g. The edge R Gamma E 2 is labeled by comp(R; E 1 ) n; m) or by 1 if comp(R; E 1 ) 2 f(0; 1) 1; 1)g or by n if comp(R; E 1 ) 2 f(l; kjl 2 f0; 1g; l k; k 1g. This notation can not be extended to ternary relationships. For that reason, in [Teo89] complexities for ternary relationships are marked by shaded areas in the relationship triangle if the relationship is many . More concrete, for instance, the E 1 corner in the triangle which represents the relationship R = E 1 ; E 2 ; E 3 ; attr(R) is not shaded if comp(R; E 2 E 3 ) 1; 1) ....

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J.T. Teorey. Database Modeling and Design: The Entity-Relationship Approach. Morgan Kaufmann Publ. San Mateo, 1989.

....calls. A fourth model, the program state machine (PSM) 9] combines the previous two models by permitting each state of a hierarchical concurrent FSM to contain actions described using program instructions. Other models include Petri nets [10] flowcharts [6, 11] entity relationship diagrams [12], Jackson diagrams [13] control dataflow graphs [14] object oriented models [15] and queueing models [16] No one model is ideal for all classes of systems. For example, the dataflow model may be most natural to use for a system that repeats the same data transformations over time on streams of ....

T. J. Teorey, Database Modeling and Design: The Entity-relationship Approach. San Mateo, California: Morgan Kaufman Publishers, 1990.

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Teorey, T.J. Database Modeling and Design: The EntityRelationship Approach, Morgan Kaufmann, 1990, Chapters 8-9.

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J. T. Teorey. Database Modeling and Design: The EntityRelationship Approach. Morgan Kaufmann, Los Altos, 1989.

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T. J. Teorey. Database Modeling and Design - the Entity-Relationship Approach. Morgan Kaufmann, 1990.

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T. J. Teorey. Database Modeling and Design - the Entity-Relationship Approach. Morgan Kaufmann, 1990.

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Teorey, T. J. (1990). Database Modeling and Design: The Entity-Relationship Approach. San Mateo, CA : Morgan Kaufman Publisher.

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J.T. Teorey. Database Modeling and Design: The Entity-Relationship Approach. Morgan Kaufmann Publ. San Mateo, 1989.

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Teorey, Toby J., Database Modeling and Design - The Entity-Relationship Approach, 3 rd ed., Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1998.

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J. T. Teorey. Database Modeling and Design: The EntityRelationship Approach. Morgan Kaufmann, Los Altos, 1989.

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