Database Normalization
Database normalization is the process of efficiently organizing data in a database. There are two reasons of the normalization process:
Eliminating redundant data, for example, storing the same data in more than one tables.
Ensuring data dependencies make sense.
Both of these are worthy goals as they reduce the amount of space a database consumes and ensure that data is logically stored. Normalization consists of a series of guidelines that help guide you in creating a good database structure.
Normalization guidelines are divided into normal forms; think of form as the format or the way a database structure is laid out. The aim of normal forms is to organize the database structure so that it complies with the rules of first normal form, then second normal form, and finally third normal form.
First Normal Form (1NF)
First normal form (1NF) sets the very basic rules for an organized database:
Define the data items required, because they become the columns in a table. Place related data items in a table.
Ensure that there are no repeating groups of data.
Ensure that there is a primary key.
First Rule of 1NF:
You must define the data items. This means looking at the data to be stored, organizing the data into columns, defining what type of data each column contains, and finally putting related columns into their own table.
For example, you put all the columns relating to locations of meetings in the Location table, those relating to members in the MemberDetails table, and so on.
Second Rule of 1NF:
The next step is ensuring that there are no repeating groups of data.
Third Rule of 1NF:
The final rule of the first normal form, create a primary key for each table which we have already created.
Second Normal Form (2NF)
Second normal form states that it should meet all the rules for 1NF and there must be no partial dependences of any of the columns on the primary key
Third Normal Form (3NF)
A table is in third normal form when the following conditions are met:
1.It is in second normal form.
2.All non primary fields are dependent on the primary key.
