oit_content_123130 - Relational Database Design Table of...

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Unformatted text preview: Relational Database Design Table of Contents Relational Database Design.............................................................2 Flat File Databases vs. Relational Databases...............................2 Term Definitions..........................................................................3 Designing a Relational Database System ........................................9 Normalizing a Database.............................................................10 Take Home Practice.......................................................................15 Relational Database Design Welcome to Relational Database Basics and Design. This class was developed to introduce the concepts used to create and maintain relational database systems. A relational database system (RDBS) is one in which two or more linked tables are used to track information. A table is a list of data about a specific subject. You may already be familiar with a flat file database. A flat file database (FFDB) is one in which a single table is used to hold all the information for a particular application. Flat file databases are commonly used to track very simple lists of information such as a personal address list. Commonly though, what seems like a simple list of information quickly becomes a complicated system. This is where good planning and a relational database become very useful . Flat File Databases vs. Relational Databases Let’s set up a simple Campus Calendar database as an example of a flat file database system. In this calendar you are going to track events that are happening on campus. This appears at first glance to be a simple list of information but let’s see what happens as you start to enter the information. Say you have information about 50 events to add to this calendar but that each event has at least two different sponsors. Your calendar would have a minimum of 100 records to start (50 events multiplied by 2 sponsors equals 100 records.) Now if an event were to be rescheduled you would have to change at least 2 records per event to ensure that the calendar was properly updated. How do you enter information about events that happen more than once, like a concert on three consecutive nights? Also what happens if a sponsor changed their name or phone number? First you would have to locate all the events that were sponsored by them and then change the information in each record (there could be up to 50 records that need to be changed). Think about what adding ticket or contact information would involve. Relational Database Design 2 As you can see from the Campus Calendar database, information tends to be repeated within flat file databases. This makes flat file databases hard to maintain and wasteful of resources such as disk space. In the Campus Calendar database, the sponsor name, address and phone number were unnecessarily repeated for each event they sponsored and date that the event occurred. Small changes such as a sponsor name change can be very difficult when...
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This note was uploaded on 02/04/2012 for the course INFORMATIO Download C taught by Professor Office during the Spring '11 term at Minnesota.

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oit_content_123130 - Relational Database Design Table of...

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