Create a conceptual design (using an E-R diagram) for the following collection of data about a university. Be sure to indicate the primary key fields.

Professors have an SSN, a name, an age, a rank, and a research specialty.

Projects have a project number, a sponsor name (e.g., WWF, NASA), a starting date, an ending date, and budget.

The Graduate students have an SSN, a name, an age, and a degree program (e.g. M.S., Ph.D.).

One professor (known as the projects principal investigator) manages each project.

One or more professors (known as the projects co-investigators) work on each project.

Professors can manage and/or work on multiple projects.

One or more graduate students (known as Grad Assistants) work on one project.

When graduate students work on a project, a professor must supervise their work on the project. Graduate students can work on multiple projects, in which case they will have a (potentially different) supervisor for each one.

Departments have a department number, a department name, and a main office.

Departments have a professor (known as the chairman) who runs the department.

The Professors work in one or more departments and for each department that they work in, a time percentage is associated with their job.

Graduate students have one major department in which they are working on their degree.

Each graduate student has another, more senior graduate student (known as the student advisor) who advises him or her on what courses to take.