title: What is the best way to choose primary key in candidate key?
body: <p>I am concerned about which candidate key to select as the <strong>primary key</strong> among the candidate keys.</p>
  <p>Assume that using mysql database(innoDB). Suppose we have a unique value, <strong>Student Number</strong>, and a unique value, <strong>ID Number(eg Social Security Number)</strong>.</p>
  <p>Student ID number and ID number can each be a candidate key.
  In this case, what value should I set as the primary key even considering auto-increment new column?</p>
  <p>My guess is that innoDB(mysql) use primary key to create the <strong>clustering index</strong>. So, is it right to use a column where I need to find a specific range, since it has the advantage of being able to find a range?</p>
  <p>Thank you!!</p>