title: ORA-01400: cannot insert NULL into even if I'm not inserting that column
body: <p>I get this error: <code>ORA-01400: cannot insert NULL into ("GRT2158A"."BUVETTE"."NUMB")</code>.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>INSERT INTO Buvette(Emplacement, NumS)
  SELECT Emplacement, NumS
  FROM GILLES_HUBERT.tp4_buvettes;
  </code></pre>
  
  <p><strong>What I do understand:</strong> NUMB is a primary key with a constraint to check if it's not null. Then, I cannot insert NULL there.</p>
  
  <p><strong>What I don't understand:</strong> I'm not even inserting the NUMB column, just <em>Emplacement</em> and <em>NumS</em>. Why does it complain about NUMB?</p>