1. Match the phenomenon to its description: dirty read, non-repeatable read, phantom read.
Difficulty: EasyType: MCQTopic: Transactions & Concurrency
A dirty read returns data that may later roll back. A non-repeatable read happens when a row read twice returns different values after another commit. A phantom read adds or removes qualifying rows between two scans of the same predicate, usually on ranges.
Example code
SELECT * FROM orders WHERE status='NEW'; -- second read returns different result set