Answer 1

Generally speaking, you should know both, they both compliment each other. I wouldn't be too concerned with titles. If this is the field you want then knowing how to perform the required tasks, brilliance in the basics and delivering solutions should be your goal. Typically, both jobs are done by the same person. You might be on a small team where some of these tasks are broken up, but for the most part, every member on the team is interchangeable, ready to step in and help where needed.