When implementing slowly changing dimensions, how do you decide whether to count changes that occur within seven days versus those that occur after seven days? Also, can you walk through the SQL syntax you would use for handling SCD type 2?

Slowly Changing Dimensions (SCD) track changes over time. When deciding whether to count changes within a seven‑day window, you consider the business requirement: if changes within seven days are considered transient, you may ignore them; if they represent a real change, you record them. For SCD type 2, you maintain historical rows by adding start and end dates and a current flag. A typical SQL snippet: INSERT INTO dim_customer (customer_id, name, start_date, end_date, current_flag) SELECT new.customer_id, new.name, CURRENT_DATE, NULL, 1 FROM new_data new LEFT JOIN dim_customer old ON new.customer_id = old.customer_id AND old.current_flag = 1 WHERE old.name <> new.name OR old.name IS NULL; UPDATE dim_customer SET end_date = CURRENT_DATE, current_flag = 0 WHERE customer_id = new.customer_id AND current_flag = 1; This logic ensures that each change creates a new row while closing the previous one. The seven‑day threshold can be applied by adding a condition on the difference between the change date and the start_date.