Entity Relationship (ER) Modeling- Learn with a Complete Example Here we are going to design an Entity Relationship (ER) model for a college database. Say we have the following statements. 1. A college contains many departments 2. Each department can offer any number of courses 3. Many instructors can work in a department 4. An instructor can work only in one department 5. For each department there is a Head 6. An instructor can be head of only one department 7. Each instructor can take any number of courses 8. A course can be taken by only one instructor 9. A student can enroll for any number of courses 10.Each course can have any number of students 2. 5 Good to go. Let's start our design. (Remember the notations we have used for entities, t attributes, relations etc. )