What's the difference between identifying and non-identifying relationships?

Question

I haven\'t been able to fully grasp the differences. Can you describe both concepts and use real world examples?

Answer 1

Let's say we have those tables:

user
--------
id
name


comments
------------
comment_id
user_id
text

relationship between those two tables will identifiying relationship. Because, comments only can be belong to its owner, not other users. for example. Each user has own comment, and when user is deleted, this user's comments also should be deleted.