Entity Relationship Model Research Papers (original) (raw)
The article examines the fundamental principles of Resource Description and Access (RDA), the new guidelines for the description and the discovery of different kinds of resources aimed to replace the AACR2 since 2013. RDA is included in... more
The article examines the fundamental principles of Resource Description and Access (RDA), the new guidelines for the description and the discovery of different kinds of resources aimed to replace the AACR2 since 2013. RDA is included in RDA Toolkit – a web site and a database containing tools and resources useful for the RDA application – which is here described in its contents and structure. The sections (attributes, relationships and appendices) are analysed in some points also through schematic tables translated in Italian. The paper examines the rules' structure and focuses on the use of numbered and unnumbered headings in RDA and in AACR former texts. RDA is analyzed as an entity/relationship data model and as a working tool for librarians too.
This article reports the results of research into software project management. the main contribution of this research is a software project management framework that consists of a static structure, shown in an entity-relationship diagram,... more
This article reports the results of research into software project management. the main contribution of this research is a software project management framework that consists of a static structure, shown in an entity-relationship diagram, and a description of each component of the framework. It also describes the procedure to design and validate the framework. This consists of integrating the solutions
1. What two conditions must be met before an entity can be classified as a weak entity? Give an example of a weak entity. To be classified as a weak entity, two conditions must be met: 1. The entity must be existence-dependent on its... more
1. What two conditions must be met before an entity can be classified as a weak entity? Give an example of a weak entity. To be classified as a weak entity, two conditions must be met: 1. The entity must be existence-dependent on its parent entity. 2. The entity must inherit at least part of its primary key from its parent entity. entity: 1. CLASS is clearly existence-dependent on COURSE. (You can database course exists.) 2. CRS_CODE. The CRS_CODE attribute is also the PK of COURSE. The conditions that define a weak entity are the same as those for a strong relationship between an entity and its parent. In short, the existence of a weak entity produces a strong relationship. And if the entity is strong, its relationship to the other entity is weak. (Note the solid relationship line in the tex decisions. For instance, if the database designer had decided to use a single-attribute as shown in 8, the CLASS entity wou CLASS_CODE, which is not derived from the COURSE entity.) In this case, the relationship between COURSE and CLASS is weak. However, regardless of how the designer classifies the relationship weak or strong CLASS is always existence-dependent on COURSE. 2. A strong relationship exists when en entity is existence-dependent on another entity and inherits at least part of its primary key from that entity. The Visio Professional software shows the strong relationship as a solid line. In other words, a strong relationship exists when a weak entity is related to its parent entity. (Note the discussion in question 1.)
The paper uses a simple example to illustrate identification of an Entity Relationship Diagram components to model a GIS database.
Distributed data - data, processed by a system, can be distributed among several computers, but it is accessible from any of them. A distributed database design problem is presented that involves the development of a global model, a... more
Distributed data - data, processed by a system, can be distributed among several computers, but it is accessible from any of them. A distributed database design problem is presented that involves the development of a global model, a fragmentation, and a data allocation. The student is given a conceptual entity-relationship model for the database and a description of the transactions and a generic network environment. A stepwise solution approach to this problem is shown, based on mean value assumptions about workload and service. A management system of a distributed database (SGBDD) is a software system that enables management and distributing BDD transparent to the user. A SGBDD consists of a single database which is decomposed into fragments, poassibly some fragments are multiplied, and each fragment or copy kept on one or more sites under the control of a local DBMS. Each site is capable of processing user queries in the local system, independently of the rest of the network, or ...
A bottom-up method for creating a hierarchy of Entity-Relationship diagrams (HERD) from a given, ‘‘flat’’ ER diagram (ERD) is proposed. The hierarchy consists of simple and interrelated diagrams - ER structures - with external... more
A bottom-up method for creating a hierarchy of Entity-Relationship diagrams (HERD) from a given, ‘‘flat’’ ER diagram (ERD) is proposed. The hierarchy consists of simple and interrelated diagrams - ER structures - with external relationships to other structures. The HERD-tree diagram, which provides the most general view of the conceptual schema, is located at the top of the hierarchy. The method is based on packaging operations, which group entities and relationships according to certain criteria. These operations are applied in several steps on a given (presumably largescale) ERD. We describe the new constructs, which are added to the ER model to enable the creation of HERD,and a bottom-up method for creating HERD. We also evaluate HERD from the point of view of user comprehension and preference, based on an experimental comparison to flat ERDs.
- by Revital Danoch and +1
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- ERD, Data Modeling, Abstraction, Entity Relationship Model, HERD
Data modeling is a process used to define and analyze data requirements needed to support the business processes within the scope of corresponding information systems in organizations. Entity-Relationship modeling is a technique used for... more
Data modeling is a process used to define and analyze data requirements needed to support the business processes within the scope of corresponding information systems in organizations. Entity-Relationship modeling is a technique used for data modeling. It is often the first step in database development lifecycle as the database developers/designers first create a conceptual model of how data items relate to each other. This tutorial teaches how to step-by-step create such models by using ER diagram (Hoffer-Prescott-Mcfadden Notation). Data modeling is a very important topic that every IT professional should know, in order to be prepared in the creation of data conceptual models, and to be able to read and understand such models.
The aim of this study was to develop business process reengineering for a supply chain of fourth range vegetable products and to set up a computerised system for managing product traceability.A framework based on event-driven process... more
The aim of this study was to develop business process reengineering for a supply chain of fourth range vegetable products and to set up a computerised system for managing product traceability.A framework based on event-driven process chains (EPCs) methodology, the entity-relationship model (ERM) and activity-based costing (ABC) is used to define and analyse the current state of a supply chain
Entity-Relationship (ER) modeling plays a major role in relational database design. The data requirements are conceptualized using an ER model and then transformed to relations. If the requirements are well understood by the designer and... more
Entity-Relationship (ER) modeling plays a major role in relational database design. The data requirements are conceptualized using an ER model and then transformed to relations. If the requirements are well understood by the designer and then if the ER model is modeled and transformed to relations, the resultant relations will be normalized. However the choice of modeling relationships between entities with appropriate degree and cardinality ratio has a very severe impact on database design. In this paper, we focus on the issues related to modeling binary relationships, ternary relationships, decomposing ternary relationships to binary equivalents and transforming the same to relations. The impact of applying higher normal forms to relations with composite keys is analyzed. We have also proposed a methodology which database designers must follow during each phase of database design.
This paper discusses the rapidly expanding environment of emerging electronic content and the importance of librarians to partner with new research and teaching communities in meeting users" needs to find, identify, select, and... more
This paper discusses the rapidly expanding environment of emerging electronic content and the importance of librarians to partner with new research and teaching communities in meeting users" needs to find, identify, select, and obtain the information and resources they need. The methodology and framework of the International Federation of Library Associations and Institutions" Functional Requirements for Bibliographic Records could serve as a useful tool in building expanded access and content systems. ********** In today's information world, whether planned or not, mature library Web sites are used as fully fledged electronic libraries. Most major academic library Web sites offer a substantial array of library services (such as reference, interlibrary loan, reserve services, instructional tutorials, and circulation), with extensive electronic collections. Increasingly, they provide direct links to numerous external discovery tools and services, which often result in c...
We developed a database compiling in vivo doses of compounds for various activities in certain animal species. The related database covers almost 100 years of experiments. The conceptual scheme of the database was created using concepts... more
We developed a database compiling in vivo doses of compounds for various activities in certain animal species. The related database covers almost 100 years of experiments. The conceptual scheme of the database was created using concepts of the entity-relationship modeling principles. Using published references, dosages and their effects on laboratory animals were entered as data. As the next stage of our work, we have started to examine the available literature to information about the experimental dosages of various drugs used in other studies. The database provides various interfaces, including graphical-user interfaces and interfaces for Internet access. The database will be useful as a knowledge infrastructure for researchers who have to perform dose-scan experiments for a specific pharmacological activity. The basic benefit of that knowledge infrastructure is that it will enable virtual pharmacological experiments that will be considerably less expensive than conventional labor...
En la práctica los esquemas Entidad Interrelación generados durante la modelación conceptual no son capaces de especificar restricciones, necesarias para garantizar la integridad de un sistema de infomación. Aunque han existido... more
En la práctica los esquemas Entidad Interrelación generados durante la modelación conceptual no son capaces de especificar restricciones, necesarias para garantizar la integridad de un sistema de infomación. Aunque han existido intentos, la comunidad de diseñadores de bases de datos no ha adoptado una práctica para el diseño de la integridad de un sistema de información dado un esquema entidad interrelación del universo de discurso. Por tanto es necesario seleccionar un lenguaje con gran nivel de captación semántica para especificar restricciones. Para ello se eligió el lenguaje natural controlado RuleSpeak, unido al Semantic of Business Vocabulary and Rules. Finalmente, se muestra la especificación de aquellas restricciones de integridad definidas por el modelador e impuestas por un agente autorizado del negocio.Palabras clave: lenguaje natural, restricciones de integridad, RuleSpeak, SBVR, sistemas de información.
Abstract. The concept of multiplicity in UML derives from that of cardinality in entity-relationship modeling techniques. The UML documentation defines this concept but at the same time acknowledges some lack of obviousness in the... more
Abstract. The concept of multiplicity in UML derives from that of cardinality in entity-relationship modeling techniques. The UML documentation defines this concept but at the same time acknowledges some lack of obviousness in the specification of multiplicities for n-ary associations. This paper shows an ambiguity in the definition given by UML documentation and proposes a clarification to this definition, as well as a simple extension to the current notation to represent other multiplicity constraints, such as participation constraints, that are equally valuable in understanding n-ary associations.
Significant effort is expended in developing a high-level conceptual schema for a relational database. However, criticalknowledge is often discarded when the conceptual schema is mapped to aset of relation schemas. As a result, designers... more
Significant effort is expended in developing a high-level conceptual schema for a relational database. However, criticalknowledge is often discarded when the conceptual schema is mapped to aset of relation schemas. As a result, designers and users must employsparser logical-level knowledge to access data. Unfortunately, naiveusers do not possess the detailed logical-level knowledge required toformulate queries corresponding to ad hoc requests.