Normalization - Normalization Motes Notes 2/7/2011...

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1 Normalization Mote’s Notes 2/7/2011 Introduction Database design is an art. Like many other art forms (painting, music, poetry), it is an art that has a solid theoretical foundation. Some of this theory is based on formal theorem and proof logic; some of it is based on years of practical experience. One of the most important theoretical foundations of database design is normalization. Database normalization is the process of reducing the data to its simplest form. This minimizes redundancies, eliminates chances of insertion, update and deletion errors, and provides the most flexible storage structure. Normalization is a multi-step process. First Normal Form (1NF) The first stage of normalization is to ensure that all data can be directly accessed by a primary key. This means that every table must have a primary key and that all compound and repeating fields must be eliminated. A compound field is one that contains multiple, distinct pieces of data. Two classic examples of compound fields are concatenated first and last names, and comma delimited addresses. Name John Smith Address 1234 Buffalo Trail, Austin, Texas, 78701 A human may have little difficulty manually dealing with these compound fields, but the database program will need to be a bit more sophisticated in order to process simple tasks like sorting the records by last name, or finding all customers living in Austin. While it is true that all database products include a substring function to allow us to parse compound fields, simply finding all addresses containing the string “Austin” may not produce the desired results. What happens with this second customer? Name
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Normalization - Normalization Motes Notes 2/7/2011...

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