To transform data into attribute–value pairs by turning columns into rows, which operation should you apply in a data flow when the VendorID column is selected?

• A. Group by
• B. Unpivot other columns
• C. Unpivot columns
• D. Remove other columns

Answer: (B)

Turning columns into rows to create attribute–value pairs is accomplished by unpivoting. When you want to keep a specific identifier column, like VendorID, fixed as the key and convert all the other columns into attribute-value pairs, you apply the unpivot operation to those other columns. This yields rows where VendorID stays as the identifier, and you get two new fields: one that captures the original column name (the attribute) and one that captures the cell value (the value).

Grouping would aggregate or summarize data rather than transform the column layout. Unpivoting all columns would also include the VendorID, which isn’t desired if you intend to preserve it as the key. Removing other columns would drop data instead of turning columns into rows. So the correct approach is to unpivot the other columns.