ER Diagram - Relational Schema

[BeetleJuice]

Hi everyone, i'm new here and was just wondering if I could get help. I have a question on an ER diagram that I am unclear about. I have being doing Oracle in Databases this year, but due to our lecturer's bout of illness (which lasted well over a month) and my own lack of consistent study I am behind. I have done the relational schema for this diagram but I want to know if there are many mistakes. If possible could I get feedback on what i've done wrong and why.

One thing I don't understand is that as a rule for m - n relationships I was told to create a seperate entity with the key consisting of the combined keys of both entity types? How would this work? I created the treatments table with two foreign keys from both entities, Patients & Doctors. Also, what are domains and how do you decide what to place as domains? I based my ones off a similiar schema.

Any help is greatly appreciated.

 

[Rabbie]

M-N relationships are best modeled by using a Junction table that will hold a foregn key from table A and a foreign key from table B.

Basically modelling two 1-M relationships.