and why is it significant? 6. What are the differences between analysis modeling and design modeling? 7. What are the basic characteristics are of object-oriented systems? 8. What is normalization and denormalization? What are the key issues in deciding between using a normalized databases and denormalized databases? 9. What is meant by service-oriented architecture? 10. How do you know when "enough is enough"? What should you look for when determining when software is ready to go into production
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Data Anomalies Normalization is the process of splitting relations into well-structured relations that allow users to inset‚ delete‚ and update tuples without introducing database inconsistencies. Without normalization many problems can occur when trying to load an integrated conceptual model into the DBMS. These problems arise from relations that are generated directly from user views are called anomalies. There are three types of anomalies: update‚ deletion and insertion anomalies. An update anomaly
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Chapter 5 Normalization of Database Tables Discussion Focus Why are some table structures considered to be bad and others good and how do you recognize the difference between good and bad structures? From an information management point of view‚ possibly the most vexing and destructive problems are created through uncontrolled data redundancies. Such redundancies produce update and delete anomalies that create data integrity problems. The loss of data integrity can destroy the usefulness
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University of Greenwich BSc (Hons) in Computing COMP1302 Database Design and Implementation Coursework Name: Student ID: Date: 1 Assumption (Ref. D1) Enterprise Rules: • • • Rule 1 Rule 2 Rule 3 The company will continue to run the business The hardware can support the company to run the business The software can support the company to run the business Business Rules: • • • • • • • Rule 1 Rule 2 Rule 3 Rule 4 Rule 5 Rule 6 Rule 7 Each Order can only hire one equipment Each Customer
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1 Solutions Review Questions 1. What is the purpose of an E-R Model? To identify the entities about which the database should store data‚ and the relationship among those entities. 2. What is an entity? An entity is any person‚ place‚ or thing having attributes‚ or characteristics‚ of interest to the organization. 3. Give an example of three entities that might exist in a database for a medical office and some of the attributes that would be stored in a table for each entity. Doctor – name‚
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Database Design Paper “A database is a structured collection of records or data that is stored in a computer system. In order for a database to be truly functional‚ it must not only store large amounts of records well‚ but be accessed easily. In addition‚ new information and changes should also be fairly easy to input.” (tech-faq.com); to ensure usefulness over the long-term‚ databases should be built with high data integrity and the ability to recover data if the hardware fails. Information that
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Principles of Distributed Database Systems M. Tamer Özsu • Patrick Valduriez Principles of Distributed Database Systems Third Edition M. Tamer Özsu David R. Cheriton School of Computer Science University of Waterloo Waterloo Ontario Canada N2L 3G1 Tamer.Ozsu@uwaterloo.ca Patrick Valduriez INRIA LIRMM 161 rue Ada 34392 Montpellier Cedex France Patrick.Valduriez@inria.fr This book was previously published by: Pearson Education‚ Inc. ISBN 978-1-4419-8833-1 e-ISBN
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CONCEPTS 1. Database A database is a logically coherent collection of data with some inherent meaning‚ representing some aspect of real world and which is designed‚ built and populated with data for a specific purpose 2. DBMS It is a collection of programs that enables user to create and maintain a database. In other words it is general-purpose software that provides the users with the processes of defining‚ constructing and manipulating the database for various applications. 3. Database system
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Functional Dependency Functional Dependency is the starting point for the process of normalization. Functional dependency exists when a relationship between two attributes allows you to uniquely determine the corresponding attribute’s value. If ‘X’ is known‚ and as a result you are able to uniquely identify ‘Y’‚ there is functional dependency. Combined with keys‚ normal forms are defined for relations. Examples Bear Number determines Student Name: BearNum ---> StuName Department Number
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the information and retain for future references. Information about the patient and the charges to be paid are also stored. The making of this system contains the following activities‚ which try to automate the entire process keeping the view of database integration approach. 1.1 Description and Background Nowadays‚ companies have invested time and money so as to grow with the fast changing times. One of the biggest and great contributions of Information Technology
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