Does an ERD prescribe an implementation approach?
One of the things that confuses me about ERDs is whether they make any prescriptions about how their relationships should be implemented technologically.
In the diagram below I'm not sure if the diagram requires these relationships to be implemented at the database level or at the application level.
Is it making any technological prescriptions or simply defining the relationship and leaving it up to me to decide how to implement it?
Would I need to have more information from the creator of the ERD before building something that is based upon it?
An ERD is not a "technological prescription" as you put it but simply a representation of logical relationships.
How you implement it - in the database or the application - is up to you.
But the database is the appropriate place to enforce these relationships.