1NF: The first normal form says that rows in the table must be unique, and attributes should be atomic. Means there shouldn't be any duplicate rows or columns in the table. In SQL this is achieved by Unique key constraints.
Before discussing the further normalization a general rule that any subsequent normal form will includ the condition before it : means for a schema to be in 2NF , 1NF should be satisfied , for 3NF both 1NF and 2 NF should satisfy.
2NF: talks about the relationship between candidate key and non - key . Every non-key shouldf be completely dependent on the complete candidate key. For ex: if a table has 2 columns as primary key then all the others should be directly related to both the primary columns.
3NF: Data model is said to be in 3 rd normal form if it satisfies 2NF and all the candidate keys are independent of each other. In simple words all the primary key columns should not be mutually depended and completely independent of each other.
Before discussing the further normalization a general rule that any subsequent normal form will includ the condition before it : means for a schema to be in 2NF , 1NF should be satisfied , for 3NF both 1NF and 2 NF should satisfy.
2NF: talks about the relationship between candidate key and non - key . Every non-key shouldf be completely dependent on the complete candidate key. For ex: if a table has 2 columns as primary key then all the others should be directly related to both the primary columns.
3NF: Data model is said to be in 3 rd normal form if it satisfies 2NF and all the candidate keys are independent of each other. In simple words all the primary key columns should not be mutually depended and completely independent of each other.
