We have a requirement from customer that if someone gets access to the database, all data that includes personal information should be encrypted, so that when they do select calls, they shouldn't be able to see anything in clear text. Now this isn't any problem for Strings, but what about bytearrays? (that can potentially be quite huge (several 100mb))

When you do a select call, you get gibberish anyways. Is it possible for a hacker to somehow read the bytes and get the sensitive information without knowing how the structure of the object it is mapped against is?
Because if that is the case, then I guess we should encrypt those bytes, even if they can potentially be quite huge. (I am guessing adding encryption will make them even bigger)