title: What are the JPA @Table annotation "catalog" and "schema" variables used for?
body: <p>Why are these important, what effect do they have on the database at hand?</p>
  
  <p>Isn't the "schema" already decided at that point, as it exists in the database?</p>
  
  <p>What exactly is a "catalog"? What kind of variable/input is the JPA catalog field expecting? Also, same question for the "schema" field.</p>