Unit 7: Introduction to Data Normalization
In this course, we have learned that entities in a database can be thought of as logical tables. Data in a table must be stored in a normalized way. First, we will identify the properties of a normalized table, learning about the process of normalization and its importance to the structure of a database. We will then study the four major steps of normalization and discuss the database anomalies that can result in the absence of normalization. Data normalization is the process of writing the data so that data redundancy is reduced and data integrity is increased.
Completing this unit should take you approximately 4 hours.
Upon successful completion of this unit, you will be able to:
- describe normalization;
- discuss and contrast the different types of dependencies;
- construct a dependency diagram; and
- normalize a relation to at least third normal form.
7.1: Defining Normalization
This subunit addresses what normalization is, why we do it, and how it is done.
This article is a concise overview of normalization: what it is, why it's done, its pros and cons, its benefits and costs, the normalization process, and 2NF to 3NF transformation.
Chapter 12 explains normalization, gives examples showing dependencies that are removed by each level of normalization, gives a dependency diagram, and introduces BCNF normalization, which is a special case of the third normal form.
Chapter 5 continues the explanation of normalization and discusses various types of anomalies and dependencies, the decomposition of poor database designs, the six levels of normalization, and normalization side effects.
These videos work through a design example. Normalization is presented as part of the design. Beginning with an initial table for the design, rules are applied that transform the design from 0NF to 1NF to 2NF and then to 3NF.
This subunit explains how normalization prevents anomalies and removes dependencies.
This short article discusses update, deletion, and insertion anomalies.
7.3: Functional Dependencies
Dependencies among attributes are a consistency risk, because a change to one attribute may result in inconsistencies with dependent attributes. Normalization removes dependencies.
Chapter 11 defines function dependency, illustrates dependencies using a sample table, and gives rules for inferring all functional dependencies.
7.4: From 1NF to BCNF
This subunit explains how a set of relations is normalized – to 1NF, to 2NF, and to BCNF (Boyce-Codd Normal Form).
This article uses functional dependencies to transform a set of relations to BCNF.
Unit 7 Assessment
- Receive a grade
Take this assessment to see how well you understood this unit.
- This assessment does not count towards your grade. It is just for practice!
- You will see the correct answers when you submit your answers. Use this to help you study for the final exam!
- You can take this assessment as many times as you want, whenever you want.