title: Difference between one-to-one and one-to-many relationship in database
body: <p>This is probably a basic(dumb) question but when having a one-to-one relationship in a database the other table has a foreign key ID(in this example). And in a one-to-many relationship the table contains many foreign keys. </p>
  
  <p>But the database does not know whether this is a one-to-one or one-to-many relationship right? The relationships that I make in an ER-Diagram is only to indicate where it should be foreign keys when making the actual tables?</p>
  
  <p>I do not completely grasp the idea of the relationships, even though I have read many tutorials about this.</p>
  
  <p>Thanks in advance.</p>