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Chapter 2. The Basics of Database Design > Planning and Designing the HelloWorl... - Pg. 41

The Basics of Database Design 41 Figure 2-1. Storing redundant data leads to extra data entry and increase the chances of your data being inaccurate Eliminating redundant data also helps you maintain accurate data. If the name of a supplier needs to be updated in multiple records, chances increase that the name will be misspelled or otherwise entered incorrectly. If your monthly expense report searches on the supplier's name, some orders could be missed if the name isn't entered correctly, so you'd have a hard time reconciling a bill. Having duplicate data in your database can lead to inconsistencies. You should store data about a single subject in each table and use table relationships to bring data together. When you structure tables correctly, you'll need to store information only once and can rely on relationships to tie information together. In the next section, we'll review some steps to ensure that the tables in a database are designed most efficiently. Quick Check Q. Name two reasons why you should remove redundant data from your database. A. Redundant data affects the accuracy of data because you have to update more records, and redundant data can have an effect on database performance. Planning and Designing the HelloWorld Database In the sections that follow, we'll examine the work that's necessary to create a dependable database that's easy for you and others to use. We'll identify processes that you can use to define the re- quirements of a database and describe how to turn those requirements into a set of tables and fields. As we explore the processes and the concepts behind the processes, we'll apply what you've learned to expand the HelloWorld database introduced in Chapter 1. We'll modify the Greetings table we created in the last chapter, breaking that table into three related tables. Later in this chapter, we'll use a wizard that Access provides to create another table the HelloWorld database requires.