title: IntegrityError: UNIQUE constraint failed: my_films.title_id
body: <p>I'm trying to insert information into my table. But I got this problem:</p>
  <pre><code>IntegrityError: UNIQUE constraint failed: my_films.title_id.
  </code></pre>
  <p>I can't understand why, because I don't have id, which repeat. Can you help me?</p>
  <p>My code:</p>
  <pre class="lang-py prettyprint-override"><code>cur.execute(&quot;&quot;&quot;CREATE TABLE my_films (
  title_id INT, 
  title TEXT, 
  premiered INT,
  rating REAL,
  PRIMARY KEY (title_id))&quot;&quot;&quot;)
  
  con.commit()
  
  films = [(1, 'Birds of Prey', 2020, 9),
      (2, 'The Avengers', 2012, 10),
      (3, 'Love Rosie', 2014, 7,6),
      (4, 'Me Before You', 2016, 7,2)]
  cur.executemany(&quot;INSERT INTO my_films VALUES (?, ?, ?, ?)&quot;, films)
  con.commit()
  </code></pre>