In a Type 1 slowly changing dimension, what happens when a non-key attribute changes?

In a Type 1 slowly changing dimension, what happens when a non-key attribute changes?

• A. The existing row is updated with the new values
• B. A new row is inserted with a new key
• C. The row is marked as deleted
• D. The non-key attribute is ignored

Answer: (A)

In a Type 1 slowly changing dimension, changes to non-key attributes are applied by updating the existing row in place, overwriting the old values. The surrogate key stays the same and no history is kept, because Type 1 does not preserve previous versions. This is different from Type 2, which would insert a new row with a new key to retain history, or Type 3, which stores a previous value in an additional field.

In a Type 1 slowly changing dimension, changes to non-key attributes are applied by updating the existing row in place, overwriting the old values. The surrogate key stays the same and no history is kept, because Type 1 does not preserve previous versions. This is different from Type 2, which would insert a new row with a new key to retain history, or Type 3, which stores a previous value in an additional field.