For example,
1. In MySQL it's common to name columns like user_name
2. In PHP you can use anything, but if you use camelCase, then it might turn out:
$userName = $user->user_name (using ORM for example)
3. In Javascript if I choose to have camelCase, which is common too, it might turn out:
fullName = user.first_name + ' ' + user.last_name
So the mix of conventions is unavoidable which is irritating.
How to deal with that?