reading-notes

Database Normalization

A process for organizing a database into tables and columns. Each table should only feature things sharing a specific topic. If each table has it’s own purpose, there is a lower chance of duplicating the data stored within your database and can keep you from having to deal with db modifications and the possible side affects.

Reasons to normalize a database:

• minimize duplicate data
• minimize/avoid data modification issues
• simplify queries

remember..It’s best for tables to have a single purpose.

Insert Anomaly- in order to create a record of something you need a primary key

Update Anomaly- If all rows are not updated, inconsistencies will appear.

Definition of Database Normalization

First Formal Form

• Data is stored in relational table, each column holding atomic values. No repeating groups of columns

Second Normal Form

• Table is in first normal form and the columns depend on table’s primary key

Third Normal Form

• Table is at second normal forms, all columns are not dependent on primary key.