title: What are the steps to take to determine a primary key
body: <p>I am having some confusion on how to determine a primary key in regards to an ERD model.</p>
  
  <p>Say for example,
     I created the following table to keep track of employees salary.</p>
  
  <p>Sal_His(Emp#, Salary, Reason, Raise-Date)</p>
  
  <p>How would I determine which key would become the primary key?</p>