Question

If one transaction is calculating an aggregate summary function on a number of records while other transactions are updating some of these records, the aggregate function may calculate some values before they are updated and others after they are updated. What is the behavior of the aggregate function in this scenario?

1) It will only calculate values after all the records have been updated
2) It will only calculate values before any records are updated
3) It will calculate some values before they are updated and others after they are updated
4) It will not calculate any values

Answer 1

Without proper concurrency controls, an aggregate summary function may calculate some values before their updates and others after, leading to inconsistent results.

Step-by-step explanation:

If one transaction is calculating an aggregate summary function on several records while other transactions are updating some of these records, the behavior of the aggregate function can be unpredictable without proper concurrency controls. Without such controls, the aggregate function may calculate some values before they are updated and others after they are updated, depending on the timing of the updates and aggregation. This can lead to inconsistent and incorrect results.