Slowly Changing Dimension Type 2 is a dimensional modeling technique used for historising changes in data, enabling organizations to track hard deletes, most of the changes and different versions of entities valid at different historical times. It manages changes in data over time by adding new records with timestamps or version numbers, preserving an audit trail of data changes and allowing for accurate historical analysis and reporting. SCD2 applications include versioning a record that changes and tracking deletions, ensuring preservation of historical data for audit and compliance purposes. A surrogate key is used to identify specific records or versions of entities in the table, enabling performance when joining fact tables. The decision flowchart helps determine the most suitable data loading strategy and write disposition based on data statefulness and change tracking needs.