Question

If the first update is overwritten by a second, it is called as a _______ update

(a) Useful

(b) Overlapping

(c) Lost

(d) Concurrent

This question was posed to me in an online interview.

I would like to ask this question from Multiversion Schemes, Snapshot Isolation topic in section Concurrency Control of RDBMS

Answer 1

Right option is (c) Lost

The explanation is: If the first update is overwritten by a second, it is called as a lost update. This generally occurs whenever two transactions are allowed to write on the database.