It is set of rules that has been established to aid in the design of tables that are meant to be connected through relationships. This set of rules is known as Normalization.
Benefits of Normalizing your database include:
1. Avoiding repetitive entries.
2. Reducing required storage space.
3. Preventing the need to restructure existing tables to accommodate new data.
4. Increased speed and flexibility of queries, sorts, and summaries.
Following are the three normal forms :-
First Normal Form
For a table to be in first normal form, data must be broken up into the smallest units possible.In addition to breaking data up into the smallest meaningful values, tables in first normal form should not contain repetitions groups of fields.
Second Normal form
In the above table of customer , city is not linked to any primary field.
Normalized customer table.
A non-key field should not depend on other Non-key field.The field "Total" is dependent on "Unit price" and "qty".