title: Foreign key reference to table in another schema
body: <p>I tried to create a foreign key on one of my tables, referencing a column of a table in a different schema.</p>
  
  <p>Something like that:</p>
  
  <pre><code>ALTER TABLE my_schema.my_table ADD (
    CONSTRAINT my_fk
      FOREIGN KEY (my_id)
      REFERENCES other_schema.other_table(other_id)
  )
  </code></pre>
  
  <p>Since I had the necessary grants, this worked fine.</p>
  
  <p>Now I wonder if there are reasons for not referencing tables in a different schema, or anything to be careful about?</p>