title: Foreign key in oracle
body: <p>I have created a table in oracle which has one FK that refers to 3 primary keys in 3 different table.But when I want to insert into it I see an error says parent key not found!what should I do?</p>
  
  <pre><code>CREATE TABLE A
  (   X       char(11)        not null,
      id      char(11)        not null,
      PRIMARY KEY(X,id),
      FOREIGN KEY(id) REFERENCES B(employee_id),
      FOREIGN KEY(id) REFERENCES C(customer_id)   
  );
  </code></pre>