MuleSoft Certified Developer – Level 1 — Question 5

A Database On Table Row listener retrieves data from a CUSTOMER table that contains a primary key user_id column and an increasing login_date_time column. Neither column allows duplicate values.
How should the listener be configured so it retrieves each row at most one time?

Answer options

• A. Set the watermark column to the login_date_time column
• B. Set the target value to the last retrieved login_date_time value
• C. Set the target value to the last retrieved user_id value
• D. Set the watermark column to the user_id column

Correct answer: A

Explanation

The correct answer is A because setting the watermark column to login_date_time ensures that each entry is retrieved only once based on the unique timestamps. Options B and C are incorrect as they do not address the mechanism to prevent duplicate retrievals effectively, while option D would not utilize the unique nature of login_date_time for sequential retrievals.