Data Normalization

Learning Objectives Define data normalization and explain its importance in preventing data anomalies. Identify data redundancy and its negative impacts on a database. Describe the rules for First Normal Form (1NF), Second Normal Form (2NF), and Third Normal Form (3NF). Convert an unnormalized table into First Normal Form (1NF). Decompose a table to meet the requirements of Second Normal Form (2NF). Decompose a table to meet the requirements of Third Normal Form (3NF). Create a simple, normalized database schema from a single, unnormalized table. Ever tried to update a friend's phone number in a messy contact list, only to find you missed an old entry? 😫 Data normalization is how we clean up that kind of digital mess! In this tutorial, you'll learn how to organ...

TermDefinitionExample Data RedundancyThe unnecessary repetition of the same piece of data in multiple places within a database. This wastes space and can lead to errors.In a table of student activities, listing the student's name and grade next to every single activity they join instead of just once in a separate student table. Data AnomalyAn error or inconsistency in the data that occurs during data insertion, deletion, or modification due to redundancy.If a teacher changes their office number, you might have to update it in 20 different rows for each class they teach. If you miss one, you have an update anomaly. Primary KeyA column (or set of columns) in a table that uniquely identifies each row. It cannot have NULL values and must be unique.A `StudentID` number is a perfect primar...

First Normal Form (1NF) 1. Each cell must contain a single, atomic (indivisible) value. 2. Each row must be unique, identified by a primary key. This is the first step. It solves the problem of having multiple values in one cell, like a list of phone numbers. To achieve 1NF, you break down these multi-valued cells into separate rows. Second Normal Form (2NF) 1. The table must be in 1NF. 2. All non-key columns must depend on the *entire* primary key (no partial dependencies). This rule applies only when you have a composite primary key. If a column only depends on one part of the composite key, you should move that column and the part of the key it depends on into a new table. Third Normal Form (3NF) 1. The table must be in 2NF. 2. No non-key column should depend on...