Which SCD type adds a new attribute to store the changed value?

Which SCD type adds a new attribute to store the changed value?

• A. Type 0 SCD
• B. Type 3 SCD
• C. Type 1 SCD
• D. Type 4 SCD

Answer: (B)

Conceptually, Type 3 SCD keeps a limited history by introducing an extra attribute to hold the value that changed. Instead of replacing the old value in place (like Type 1) or creating a new row for each change (like Type 2), you add a new column to store the previous (or changed) value. This lets you see both the current value and the immediately prior value in the same row, giving a light-weight history without full versioning. It’s especially useful when you only need to track the most recent change or two without expanding the number of rows.

Conceptually, Type 3 SCD keeps a limited history by introducing an extra attribute to hold the value that changed. Instead of replacing the old value in place (like Type 1) or creating a new row for each change (like Type 2), you add a new column to store the previous (or changed) value. This lets you see both the current value and the immediately prior value in the same row, giving a light-weight history without full versioning. It’s especially useful when you only need to track the most recent change or two without expanding the number of rows.