Question

Explain the normal forms 1NF, 2NF, and 3NF. Discuss how normal forms can be transformed from lower normal forms to higher normal form (i.e. 1NF to 2NF to 3NF).  

Answer 1

Normalization helps in assessing and correcting database structure (i.e. table) in order to reduce the data redundancies and anomalies. This helps in assigning attributes to tables on the basis of determination. There are types of normal forms, such as, first normal form (1NF), second normal form (2NF), third normal form (3NF), etc.

To have the right data structure in place it is important to have higher normal form and which are far better than lower normal forms. The concept of normalization is helpful when designing a new database and its structure as it will help in analyzing the association among the attributes within every entity and helps to identify if any improvement is needed in the structures and to have appropriate design of the database.

In the 1NF, each table cell should have a single value and records should be unique. In this the case the repeating groups are eliminated, determining the primary key (i.e. single value which determines the database record uniquely) and related dependencies. This will provide the overall overview of the association between various table attributes.

In 2NF, there are two rules apply, i.e. should have 1NF in place and should have single column primary key. Thus, to have new tables it is important to eliminate partial dependencies and have the table partitioned into two or more tables. Hence, it is important that it should not have any partial dependencies.

For 3NF, it is important to have 2NF in place and no “transitive functional dependencies” (i.e. when changing any non-key entity or column, it may change the other non-key entity). Hence, it becomes important to make new tables to avoid this situation and if needed then should reassign related dependent attributes.