Question

I have in models.py:

class Team(models.Model):
    x = models.IntegerField()
    y = models.IntegerField()

    a = models.IntegerField()
    b = models.IntegerField()

    def get_stat(self):
        return {
            'xy': self.x + self.y,
            'ab': self.a + self.b
        }

    stat = property(get_stat)

In team.html I have:

xy stat: {{ team.stat.xy }}
ab stat: {{ team.stat.ab }}

The question is: “does django executes get_stat function everytime I call stat or it caches result?”

Answer 1

No, property does not cache any results.

If you wanted it cached for heavy repeated access, the typical design pattern is:

def get_stat(self):
    if not hasattr(self, '__get_stat'):
         self.__get_stat =  {
            'xy': self.x + self.y,
            'ab': self.a + self.b
         }
    return self.__get_stat

Of course, this doesn’t work if are doing something odd like dealing with instances that are modified in place, but not commited to the DB. I belive 99% of uses involve DB->Object->Action