chapter 2 - COP 4710: Database Systems Fall 2009 Chapter 2...

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COP 4710: Database Systems (Chapter 2) Page 1 © Mark Llewellyn COP 4710: Database Systems Fall 2009 Chapter 2 – Introduction to Data Modeling School of Electrical Engineering and Computer Science University of Central Florida Instructor : Mark Llewellyn markl@cs.ucf.edu HEC 236, 407-823-2790 http://www.cs.ucf.edu/courses/cop4710/fall2009
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COP 4710: Database Systems (Chapter 2) Page 2 © Mark Llewellyn Semantic data models attempt to capture the “meaning” of a database. Practically, they provide an approach for conceptual data modeling. Over the years there have been several different semantic data models that have been proposed. By far the most common is the entity-relationship data model , most often referred to as simply the E-R data model . The E-R model is often used as a form of communication between database designers and the end users during the developmental stages of a database. Introduction to Data Modeling
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COP 4710: Database Systems (Chapter 2) Page 3 © Mark Llewellyn The E-R model contains an extensive set of modeling tools, some of which we will not be concerned with as our primary objective is to give you some insight into conceptual database design and not learning all of the ins and outs of the E-R model. Another conceptual modeling which is becoming more common is the Object Definition Language (ODL) which is an object-oriented approach to database design that is emerging as a standard for object-oriented database systems. Introduction to Data Modeling (cont.)
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COP 4710: Database Systems (Chapter 2) Page 4 © Mark Llewellyn The database design process can be divided into six basic steps. Semantic data models are most relevant to only the first three of these steps. 1. Requirements Analysis: The first step in designing a database application is to understand what data is to be stored in the database, what applications must be built on top of it, and what operations are most frequent and subject to performance requirements. Often this is an informal process involving discussions with user groups and studying the current environment. Examining existing applications expected to be replaced or complemented by the database system. Database Design
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COP 4710: Database Systems (Chapter 2) Page 5 © Mark Llewellyn 2. Conceptual Database Design: The information gathered in the requirements analysis step is used to develop a high- level description of the data to be stored in the database, along with the constraints that are known to hold on this data. 3. Logical Database Design : A DBMS must be selected to implement the database and to convert the conceptual database design into a database schema within the data model of the chosen DBMS. Database Design (cont.)
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COP 4710: Database Systems (Chapter 2) Page 6 © Mark Llewellyn 4. Schema Refinement : In this step the schemas developed in step 3 above are analyzed for potential problems. It is in this step that the database is normalized . Normalization of a database is based upon some elegant and powerful mathematical theory. We will discuss normalization later in the term.
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chapter 2 - COP 4710: Database Systems Fall 2009 Chapter 2...

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