The process to alter the structure of a database is basically categorized into two ways one is Normalization and other is Denormalization.
The following are the important differences between Normalization and Denormalization.
| Sr. No. | Key | Normalization | Denormalization |
|---|---|---|---|
| 1 | Implementation | Normalization is used to remove redundant data from the database and to store non-redundant and consistent data into it. | Denormalization is used to combine multiple table data into one so that it can be queried quickly. |
| 2 | Focus | Normalization mainly focuses on clearing the database from unused data and to reduce the data redundancy and inconsistency. | Denormalization on the other hand focus on to achieve the faster execution of the queries through introducing redundancy. |
| 3 | Number of Tables | During Normalization as data is reduced so a number of tables are deleted from the database hence tables are lesser in number. | On another hand during Denormalization data is integrated into the same database and hence a number of tables to store that data increases in number. |
| 4 | Memory consumption | Normalization uses optimized memory and hence faster in performance. | On the other hand, Denormalization introduces some sort of wastage of memory. |
| 5 | Data integrity | Normalization maintains data integrity i.e. any addition or deletion of data from the table will not create any mismatch in the relationship of the tables. | Denormalization does not maintain any data integrity. |
| 6 | Where to use | Normalization is generally used where number of insert/update/delete operations are performed and joins of those tables are not expensive. | On the other hand Denormalization is used where joins are expensive and frequent query is executed on the tables. |