Relational database design using an object-oriented methodology
TL;DR: A comprehensive explanation and two applications show the semantic improvement of OMT over other approaches to relational database design.
Abstract: Of the many approaches to relational database design, the Object Modeling Technique (OMT) is particularly effective. A comprehensive explanation and two applications show the semantic improvement of OMT over other approaches.
Citations
More filters
01 Dec 1987
TL;DR: The object-relation model, which combines the object-oriented model with the entity-relationship model from data base theory, is particularly useful for designing and partitioning systems of interrelated objects.
Abstract: The relation as a semantic construct in an object-oriented language clearly expresses associations and constraints among objects which would otherwise be buried in implementation code. The externalization of references between objects permits a symmetric, non-redundant conceptual model which merits its own special notation and predefined operations. The object-relation model, which combines the object-oriented model with the entity-relationship model from data base theory, is particularly useful for designing and partitioning systems of interrelated objects. Relations can be implemented efficiently using hash tables. The model proposed here has been fully implemented in an object-oriented language written by the author which has been used to implement several production applications.
268 citations
Patent•
13 Sep 1994
TL;DR: In this paper, the system allows a user to create a semantic object data model of the database schema, which is defined by one or more semantic objects, each of which includes attributes that describe a characteristic of the semantic objects.
Abstract: A computer-based system for allowing a user to create a relational database schema. The system allows a user to create a semantic object data model of the database schema. The semantic object data model is defined by one or more semantic objects, each of which includes one or more attributes that describe a characteristic of the semantic objects. The attributes are defined as being either simple value attributes that describe a single characteristic of the semantic object; group attributes that include one or more member attributes that collectively describe a characteristic of the semantic object; formula attributes that set forth a computation that describes a characteristic of a semantic object; or object link attributes that define a relationship between two or more semantic objects. Once the semantic object data model is created, the system validates the semantic objects to ensure no modeling errors have been made and transforms the semantic objects and their included attributes into a plurality of relational database tables that will store data as defined by the semantic object data model.
250 citations
01 Oct 1993
TL;DR: This article explores some of the lesser-recognized semantic relationships and discusses both how they could be captured, either manually or by using an automated tool, and their impact on database design.
Abstract: To develop sophisticated database management systems, there is a need to incorporate more understanding of the real world in the information that is stored in a database. Semantic data models have been developed to try to capture some of the meaning, as well as the structure, of data using abstractions such as inclusion, aggregation, and association. Besides these well-known relationships, a number of additional semantic relationships have been identified by researchers in other disciplines such as linguistics, logic, and cognitive psychology. This article explores some of the lesser-recognized semantic relationships and discusses both how they could be captured, either manually or by using an automated tool, and their impact on database design. To demonstrate the feasibility of this research, a prototype system for analyzing semantic relationships, called the Semantic Relationship Analyzer, is presented.
232 citations
Cites background from "Relational database design using an..."
.../s-a), aggregation (component), and association (membership) relationships (Smith and Smith, 1977; Blaha et al., 1988; Mattos, 1988; Potter and Kerschberg, 1988; Davis and Bonnell, 1989; Mattos and Michels, 1989; Goldstein and Storey, 1991, 1992)....
[...]
...If the part entity type can be considered independently of its attachment to the aggregate (Blaha et al., 1988), then the minimum cardinality is 0....
[...]
TL;DR: The diffusion of technology to end users who can now develop their own information systems raises issues concerning the cost, quality, efficiency, and accuracy of such systems.
Abstract: The diffusion of technology to end users who can now develop their own information systems raises issues concerning the cost, quality, efficiency, and accuracy of such systems
230 citations
Patent•
03 Jun 1996
TL;DR: In this paper, a relational database is modified to reflect changes made in the corresponding object model based upon the differences between the current and proposed relational database schemas, and the database is updated to reflect these changes.
Abstract: An object model comprises one or more semantic objects that represent items about which data is stored in a relational database in a computer system. Each semantic object has one or more components that define the data stored for each item. The object model is mapped into a current relational database schema. As a user makes changes to the model the computer system generates a proposed relational database schema, and the differences between the current relational database schema and the proposed relational database schema are determined. The relational database is modified to reflect changes made in the corresponding object model based upon the differences between the current and proposed relational database schemas.
190 citations
References
More filters
Book•
17 Oct 2013TL;DR: A data model, called the entity-relationship model, is proposed that incorporates some of the important semantic information about the real world and can be used as a basis for unification of different views of data: the network model, the relational model, and the entity set model.
Abstract: A data model, called the entity-relationship model, is proposed. This model incorporates some of the important semantic information in the real world. A special diagramatic technique is introduced as a tool for data base design. An example of data base design and description using the model and the diagramatic technique is given. Some implications on data integrity, information retrieval, and data manipulation are discussed.The entity-relationship model can be used as a basis for unification of different views of data: the network model, the relational model, and the entity set model. Semantic ambiguities in these models are analyzed. Possible ways to derive their views of data from the entity-relationship model are presented.
5,941 citations
Book•
PARC1
TL;DR: This book is the first detailed account of the Smalltalk-80 system and is divided into four major parts: an overview of the concepts and syntax of the programming language, a specification of the system's functionality, and an example of the design and implementation of a moderate-size application.
Abstract: From the Preface (See Front Matter for full Preface)
Advances in the design and production of computer hardware have brought many more people into direct contact with computers. Similar advances in the design and production of computer software are required in order that this increased contact be as rewarding as possible. The Smalltalk-80 system is a result of a decade of research into creating computer software that is appropriate for producing highly functional and interactive contact with personal computer systems. This book is the first detailed account of the Smalltalk-80 system. It is divided into four major parts:
Part One -- an overview of the concepts and syntax of the programming language.
Part Two -- an annotated and illustrated specification of the system's functionality.
Part Three -- an example of the design and implementation of a moderate-size application.
Part Four -- a specification of the Smalltalk-80 virtual machine.
3,882 citations
"Relational database design using an..." refers background in this paper
...The Object Modeling Technique (OMT) The Smalltalk- programming language [3] demonstrates many object oriented concepts....
[...]
22 Sep 1975
TL;DR: A data model, called the entity-relationship model, which incorporates the semantic information in the real world is proposed, and a special diagramatic technique is introduced for exhibiting entities and relationships.
Abstract: A data model, called the entity-relationship model, is proposed. This model incorporates some of the important semantic information about the real world. A special diagrammatic technique is introduced as a tool for database design. An example of database design and description using the model and the diagrammatic technique is given. Some implications for data integrity, information retrieval, and data manipulation are discussed.The entity-relationship model can be used as a basis for unification of different views of data: the network model, the relational model, and the entity set model. Semantic ambiguities in these models are analyzed. Possible ways to derive their views of data from the entity-relationship model are presented.
3,693 citations
TL;DR: A database design methodology is defined for the design of large relational databases that produces database designs that are not only accurate representations of reality, but flexible enough to accommodate future processing requirements.
Abstract: A database design methodology is defined for the design of large relational databases. First, the data requirements are conceptualized using an extended entity-relationship model, with the extensions being additional semantics such as ternary relationships, optional relationships, and the generalization abstraction. The extended entity-relationship model is then decomposed according to a set of basic entity-relationship constructs, and these are transformed into candidate relations. A set of basic transformations has been developed for the three types of relations: entity relations, extended entity relations, and relationship relations. Candidate relations are further analyzed and modified to attain the highest degree of normalization desired.The methodology produces database designs that are not only accurate representations of reality, but flexible enough to accommodate future processing requirements. It also reduces the number of data dependencies that must be analyzed, using the extended ER model conceptualization, and maintains data integrity through normalization. This approach can be implemented manually or in a simple software package as long as a "good" solution is acceptable and absolute optimality is not required.
789 citations
"Relational database design using an..." refers background or methods in this paper
...High level (abstraction) Logical data model I + Mapping of object structures to tables Candidate keys No-null attributes Domains Frequently accessed attributes Teorey’s Logical Relational Design Methodology (LRDM) Scores of papers have been written on variations of the ER method....
[...]
...Our OMT-based approach builds upon LRDM as follows: 1....
[...]
...Similarly, LRDM is more powerful than ER....
[...]
...The Object Modeling Technique (OMT) improves upon the ER and LRDM approaches....
[...]
...The ER method uses the term relationship in a different and much narrower sense than LRDM and OMT....
[...]
[...]
01 Jun 1986
TL;DR: A data model is defined that can directly describe complex objects, and it is shown that identity can easily be incorporated in it and that a surrogate-based implementation scheme is needed to support the strong notion of identity.
Abstract: Identity is that property of an object which distinguishes each object from all others. Identity has been investigated almost independently in general-purpose programming languages and database languages. Its importance is growing as these two environments evolve and merge.We describe a continuum between weak and strong support of identity, and argue for the incorporation of the strong notion of identity at the conceptual level in languages for general purpose programming, database systems and their hybrids. We define a data model that can directly describe complex objects, and show that identity can easily be incorporated in it. Finally, we compare different implementation schemes for identity and argue that a surrogate-based implementation scheme is needed to support the strong notion of identity.
495 citations