title: How do I record daily rankings for a model in Django?
body: <p>I have a model to which I have to record a <code>PositiveSmallIntegerField</code> to the object, that is updated daily with the relevant score.</p>
  
  <pre><code>class Student(models.Model):
      name = models.CharField(max_length=20)
      grade = models.ForeignKey(Grade)
      rank = ??
  </code></pre>
  
  <p>The number of objects with this model will never exceed 100 and the scores/ranks must be retained for a period of 180 days. The database is Postgresql 9.2.</p>
  
  <p>The rank is calculated daily on the score from another app, which I want to store in the database related to the student model, where I'm stuck with the model design, I have no Idea, what should be done for the ranks? Is there a repeating field in Django? </p>
  
  <p>Any clues or experiences will be much appreciated</p>
  
  <p>thanks.</p>
  
  <h3>Update:(Adding an example)</h3>
  
  <p>The database must look something like this,</p>
  
  <pre><code>+---------+-------+----------+----------+----------+----------+----------+----------+
  | Student | Grade | 08-01-15 | 08-02-15 | 08-03-15 | 08-04-15 | 08-05-15 | 08-06-15 |
  +---------+-------+----------+----------+----------+----------+----------+----------+
  | Alex    |     5 |        2 |        1 |        1 |        2 |        3 |        2 |
  | John    |     5 |        3 |        2 |        3 |        4 |        2 |        4 |
  | Susan   |     5 |        1 |        4 |        2 |        1 |        1 |        1 |
  | Zara    |     5 |        4 |        3 |        4 |        3 |        4 |        3 |
  +---------+-------+----------+----------+----------+----------+----------+----------+
  </code></pre>
  
  <p>The rank of the student must be stored for the days like shown here, for the day 1, the ranks must be stored in a column/anything similar, and the number of days must go on for the consecutive 180 days, the ranks for each day must be added to the consecutive days.</p>
  
  <p>I'm not stuck with the save method, but about the field where to save the calculated ranks. </p>