title: Can't Drop foreign key in MySQL
body: <p>I have had a 1 to many relationship between course and instructor, which I wanted to drop. When I tried to drop the instructorID in course table it told me that. I couldn't drop it as it was a foreign key. Then I decided to drop it like this:</p>
  
  <pre><code>ALTER TABLE course DROP FOREIGN KEY instructorID
  </code></pre>
  
  <p>But i get this error : </p>
  
  <pre><code>#1091 - Can't DROP 'InstructorID'; check that column/key exists 
  </code></pre>
  
  <p>I don't get what this error means. what am i doing wrong? </p>