title: Check for empty column and set value to it in SQLAlchemy
body: <p>I have model, which is look like this</p>
  
  <pre><code>class Question(db.Model):
      __tablename__ = 'questions'
      id = db.Column(db.Integer, primary_key=True)
      question_title = db.Column(db.String(64))
      question_text = db.Column(db.String(256), nullable=False)
      votest = db.Column(db.Integer, default=0)
      answers = db.relationship('Answer', backref='question')
  
      def __repr__(self):
          return '&lt;QTitle: %s&gt;\n&lt;QText: %s&gt;' % (self.question_title,
                                            self.question_text)
  </code></pre>
  
  <p>The thing is to check if column <code>question_title</code> is empty, and assign it to first 64 symbols of column <code>question_text</code> + '...'.
  Which is the best way to implement this?</p>
  
  <p>Maybe the best way is not to implement this in <strong><code>model</code></strong>, but make this check in <strong><code>view</code></strong>?</p>