I just found out on Django document, there's an example that's for
manytomany, using 'through' when defining the foreign key. I think this is
what i need.
Here's the example:
from django.db import models
class Person(models.Model):
name = models.CharField(max_length=128)
def __str__(self): # __unicode__ on Python 2
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership')
def __str__(self): # __unicode__ on Python 2
return self.name
class Membership(models.Model):
person = models.ForeignKey(Person, on_delete=models.CASCADE)
group = models.ForeignKey(Group, on_delete=models.CASCADE)
date_joined = models.DateField()
invite_reason = models.CharField(max_length=64)
On Wednesday, June 21, 2017 at 2:49:40 PM UTC-7, Kevin Yu wrote:
>
> I'm working with a legacy database so I have to set managed=False in the
> model. Here's the 3 related tables:
>
>
> class Branches(models.Model):
> name = models.CharField(max_length=128)
> branchpoint_str = models.CharField(max_length=255)
> dev_lead_id = models.IntegerField(blank=True, null=True)
> source = models.CharField(max_length=255)
> state = models.CharField(max_length=255)
> kind = models.CharField(max_length=255)
> desc = models.TextField(blank=True, null=True)
> approved = models.IntegerField()
> for_customer = models.IntegerField()
> deactivated_at = models.DateTimeField(blank=True, null=True)
> created_at = models.DateTimeField(blank=True, null=True)
> updated_at = models.DateTimeField(blank=True, null=True)
> codb_id = models.IntegerField(blank=True, null=True)
> pm_lead_id = models.IntegerField(blank=True, null=True)
> version = models.CharField(max_length=20, blank=True, null=True)
> path_id = models.IntegerField(blank=True, null=True)
> branchpoint_type = models.CharField(max_length=255, blank=True,
> null=True)
> branchpoint_id = models.IntegerField(blank=True, null=True)
>
> class Meta:
> managed = False
> db_table = 'branches'
> verbose_name_plural = 'Branches'
>
> class Projects(models.Model):
> id = models.AutoField(primary_key=True)
> name = models.CharField(max_length=40, primary_key=True)
> status = models.CharField(max_length=255)
> platform = models.CharField(max_length=255)
> enabled = models.IntegerField()
> path = models.CharField(max_length=128, blank=True, null=True)
> tag_prefix = models.CharField(max_length=64, blank=True, null=True)
> created_at = models.DateTimeField(blank=True, null=True)
> updated_at = models.DateTimeField(blank=True, null=True)
> codb_id = models.IntegerField(blank=True, null=True)
> template = models.CharField(max_length=64, blank=True, null=True)
> image_path = models.CharField(max_length=128, blank=True, null=True)
> repository_id = models.IntegerField(blank=True, null=True)
> number_scheme = models.CharField(max_length=32)
> special_dir = models.CharField(max_length=32, blank=True, null=True)
> project_family_id = models.IntegerField()
> class Meta:
> managed = False
> db_table = 'projects'
> verbose_name_plural = 'projects'
>
> class BranchesProjects(models.Model):
> # project_id = models.IntegerField()
> # branch_id = models.IntegerField()
> project = models.ForeignKey(Projects, on_delete=models.CASCADE)
> branch = models.ForeignKey(Branches, on_delete=models.CASCADE)
>
> class Meta:
> managed = False
> db_table = 'branches_projects'
>
> I have been able to do the join using raw(). However, the return object is
> rawqueryset. What I want is queryset so that I can use django-filter to
> process it. My current raw sql is like this:
> Branches.objects.raw(
> '''SELECT br.id, br.name, br.created_at, br.updated_at,
> br.branchpoint_str, br.source
> FROM branches as br
> LEFT JOIN branches_projects as bp
> ON br.id = bp.branch_id
> WHERE bp.project_id = "%s" AND source != "other"
> ORDER BY updated_at DES'''
>
>
> My question is, is there a way to achieve the same result using Django's
> queryset? I've also explored the idea of using the extra() in django
> extra
> <https://docs.djangoproject.com/en/1.11/ref/models/querysets/#django.db.models.query.QuerySet.extra>
> but
> it doesn't really work for me.
>
>
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