[jascha_eng]

This actually used to be one of my favorite interview questions for backend engineers. Everyone has used transactions but depending on your seniority you'd understand it to different degrees.

And no I'd never expect people to know the isolation levels by heart, but if you know there are different ones and they behave differntly that's pretty good and tells me you are curious about how things work under the hood.

[layer8]

The nominally same isolation levels can also behave differently on different database systems, so in general you have to investigate the details on a case-by-case basis anyway.