In Type 2 Slowly Changing Dimension, a new record is added to the table to represent the new information. Therefore, both the original and the new record will be present. The new record gets its own primary key.
In our example, recall we originally have the following table:
| Customer Key | Name | State |
| 1001 | Guru | Jharkhand |
After Guru moved from Illinois to California, we add the new information as a new row into the table:
| Customer Key | Name | State | Active |
| 1001 | Guru | Jharkhand | 0 |
| 1005 | Guru | Karnataka | 1 |
Advantages:
- This allows us to accurately keep all historical information.
Disadvantages:
- The table size may increase due to historical data.
When to use Type 2:
Type 2 slowly changing dimension should be used when it is necessary for the data warehouse to track historical changes.
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