In relational dbms, it is used to
- Reduce redundancy / duplications
- Increase speed of transactions
- Improves integrity
- mostly used 1NF, 2NF, 3NF
1 NF:
- First normal form
- Each cell contains single value
- Each row is unique
2NF:
- Second normal form
- Database must be in 1NF
- Separata table for values that occur frequently in multiple rows for same column
- Make sure to connect the separate table with a foreign key
3NF:
- Third normal form
- Database must be in 2NF
- If a column in a table does not depend on that table's primary key,
then separate that unrelated column
- Make sure to connect the separate table with a foreign key