SQL Type Baby, This Is Work

Single object transactions must be atomic and isolated, right? So what happens if you're writing a block of data but the connection was interrupted in the middle of the right? That's one situation where things should go wrong. What if there was a failure while updating an old block of data? So now you have a mixture of new and old, like what happens then? Reading values while in the process of updating. It's only halfway through. What do I get back as the reader, right? so those are things you have to think about.