If you’re learning SQL server then you’ll often stumble onto term called “normalization”. So in this article we’ll discuss what normalization is and what are the different types of normalization.
What is normalization ?
It is set of rules that have 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.
Why normalize ?
There are many benefits of normalization because of which in many situation there is need to normalize the data.
1. Avoiding repetitive entries
2. Reducing required storage space
3. Preventing the need to restructure existing tables to accomodate new data
4. Increased speed and flexibility of queries, sorts and summaries
Types of Normalization
Let’s take a look at some of the type of normalization:
1. First Normal Form
To qualify for the 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.
2. Second Normal Form
To qualify for the second normal form each field in a multiple field primary key table must be directly related to the entire primary key. Or in the other words. each non-key field should be a fact about all the fields in the primary key.
3. Third Normal Form
To qualify for third normal form, a non-key should not depend on other non-key field.
There are two more normalized form called “foruth & fifth normal form”.
De-normalization
De-normalization is the process of putting one fact in numerous places. Only valid reason exists for de-normalizing a relational design- to enhance performance or if we are doing data warehousing and data mining. The sacrifice to performance is that you increase redundancy in database.