NORMALIZATION

NORMALIZATION

1. 1st Normal Form

   • No repeating data/fields
   • Unique field Names
   • Primary Key
   • It should only have single(atomic) valued attributes/column
   • Advantages of using 1st NF
     • It allows you to query and sort data for orders very quickly because you search only one column—Order Number.
     • It allows you to create any number of orders for each customer without having to add new columns.

2. 2nd Normal Form

   • Already in 1NF
   • All non-key fields are dependent on the whole PK
   • All field data can be found by looking at entire PK
   • Advantages of using 2nd NF
     • Redundant data is reduced more effectively.
     • Data is consistent in the database.
     • It improves the flexibility in designing a Database.
     • It also improves the security of the database.

3. 3rd Normal Form

   • Already in 2NF
   • Advantages of using 3rd NF
     • Ensures no data duplication
     • Increases efficiency for the running of queries.
     • Reduces amount of storage required.
   • No functional dependency between non-key fields

4. ADVANTAGES

   • Less storage space needed, so smaller hard drive
   • Easier to maintain a database
   • Flexibility for expanding database in future
   • Increased data integrity - so only one copy correct

5. DISADVANTAGES

   • May not meet the needs of the company i.e. store address as one field
   • Reduces database performance - more tables = slower processing
   • Results of historical calculations can't be stored