Types of SCD

The various types of SCD are described as follows:

• Type 1 dimension mapping (SCD1): This keeps only current data and does not maintain historical data.

Note

Use SCD1 mapping when you do not want history of previous data.

• Type 2 dimension/version number mapping (SCD2): This keeps current as well as historical data in the table. It allows you to insert new records and changed records using a new column (PM_VERSION_NUMBER) by maintaining the version number in the table to track the changes. We use a new column PM_PRIMARYKEY to maintain the history.

Note

Use SCD2 mapping when you want to keep a full history of dimension data, and track the progression of changes using a version number.

• Consider there is a column LOCATION in the EMPLOYEE table and you wish to track the changes in the location on employees. Consider a record for Employee ID 1001 present in your EMPLOYEE dimension table. Steve was initially working in India and then shifted to USA. We are willing to maintain history on the...