Re: managers or classmethods?

[bruno desthuilliers]

On Feb 25, 5:51 am, HARRY POTTRER  wrote:
> Why not something like this:
>
> class Person(models.Model):
>     @classmethod
>     def male(cls):
>         return cls.objects.filter(gender='M')
>
>     @classmethod
>     def female(cls):
>         return cls.objects.filter(gender='F')
>
>     name = models.CharField(maxlength=20)
>     gender = models.CharField(maxlength=1)
>
> instead of defining a 'female' and 'male' custom managers as is
> illustrated in the docs? Whenever I need to define 'table level'
> functionality, I've always gone with the above method rather than
> bother with a custom manager. What am I missing out on?

I don't find the doc example to be really that great FWIW. As far as
I'm concerned, I'd define 'male' and 'female' as methods of the same
custom manager. But anyway:

- custom managers let you do much more than just adding a couple
shortcuts,
- custom managers can be used as "related" managers - that is, when
traversing a relationship between to models.
- personal tastes here, but I like having the 'table-level' operations
properly namespaced.

Point #2 can be really useful for some relatively complex models /
relationships / bussiness rules, even if the way related_managers are
currently created makes for sometimes a bit hackish code.

My 2 cents...

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managers or classmethods?

[HARRY POTTRER]

Why not something like this:

class Person(models.Model):
@classmethod
def male(cls):
return cls.objects.filter(gender='M')

@classmethod
def female(cls):
return cls.objects.filter(gender='F')

name = models.CharField(maxlength=20)
gender = models.CharField(maxlength=1)

instead of defining a 'female' and 'male' custom managers as is
illustrated in the docs? Whenever I need to define 'table level'
functionality, I've always gone with the above method rather than
bother with a custom manager. What am I missing out on?

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