Consider the following relational conceptual database schema for keeping track of course registration of students: Courses (Code, Title, Dept) Registered (SSN, Code) Students (SSN, Name, Dept, GPA) a) Indicate the Primary key for each relation b) List all foreign keys c) Write SQL commands to create this database in which you must specify all necessary integrity constraints including those that are related to foreign keys (such as on delete, on update)