Question

Single entity having more than one role in the same relationship is an example of

Answer 1

Goal of design is to generate a formal specification of the database schema

Methodology:

Use E-R model to get a high-level graphical view of the essential components of the enterprise and how these components are related

We then convert the E-R diagram to SQL DDL, or whatever database model you are using

E-R Model is not SQL-based. It's not tied to any particular DBMS. It is a conceptual and semantic model, which attempts to capture meanings rather than an actual implementation.