0

we are tasked with creating a database which has three entities team, user, course. A course will have multiple students and multiple teams in it. A student and professor can belong to many courses. However, a user with the type of student can only belong to one team in a specific course, but they can belong to other teams in different courses. We are currently trying to figure out how to display this relationship. We are also leaning towards teams being a weak entity which depends on course. So far we have two versions of how we believe the entities and relationships will look like. Would someone be able to tell if we are on the correct track, the weak entity is throwing us off. We also are a bit confused on the cardinality for the ternary relationship. We only put primary keys in the diagram to simplify it.

A user has the following attributes: name, primary key(userID), userType(either admin, student,teacher), and email.
A course has the following attributes: course name, primary key(course id), start date, and end date.
A team is a weak entity with the following attributes: course id, team number. Primary key(course id, team number).

Thank you to anyone who may be able to help.

this_geek1991
  • 1
  • 1

1 Answers1

0

IMO, the course table should not have both team and user linked to it, only team should be linked to it, to specify what course is the team for. My ERD diagram would look something similar to this : ERD diagram

Team_member is an associative entity used to solve the many-to-many relationship between team and user, since each user can belong to many teams, and each team can have many members, so it should have a composite key made up of user_id and team_id, to record each member within a team, and team should have a foreign key of course_id to specify its course.

YUNG FOOK YONG
  • 109
  • 1
  • 11