Assginment 1: 
Part 1 on ER diagram common mistakes:
1) Chair person as an attribute of Department 
  Correct:  a relationship between professor and the department 
2) Prerequisite as an entity 
  Correct:  a recursive relatioships of courses 
3) Course as a strong entity
 Correct:  course is a weak entity identified through department 
4) Student evaluation is a realtionship between a teacher and a student. 
Correct: evaluation is an attribute of class enrollment
5) Missing cardinality.

Part 2: Relational schema common mistakes:
1) Missing or incorrect identification of foreign keys
correct: e.g. Chairperson should be a foreign key referring to professor ID
2) Incorrect keys for courses
correct: courseID + departmentID
3) Missing certain relationships
Correct: e.g. teaching relationships should be reflected by either adding professorID to the course table or at least an independent table recording professorID and CourseKey (CourseID + departID)
4) Prerequsite as an entity.
Correct: Prerequisite (Course1 (CourseId + departmentID), Course2 (CourseId + departmentID))