python django model联合主键

https://docs.djangoproject.com/en/2.0/topics/db/models/#meta-options

Meta

options¶

Give your model metadata by using an inner

class Meta

, like so:

from django.db import models

class Ox(models.Model):
horn_length = models.IntegerField()

class Meta:
ordering = ["horn_length"]
verbose_name_plural = "oxen"

Model metadata is “anything that’s not a field”, such as ordering options(

ordering

), database table name (

db_table

), orhuman-readable singular and plural names (

verbose_name

and

verbose_name_plural

). None are required, and adding

classMeta

to a model is completely optional.A complete list of all possible

Meta

options can be found in the modeloption reference.

https://docs.djangoproject.com/en/2.0/ref/models/options/#unique-together

unique_together

¶

Options.

unique_together

¶Sets of field names that, taken together, must be unique:

unique_together = (("driver", "restaurant"),)

This is a tuple of tuples that must be unique when considered together.It’s used in the Django admin and is enforced at the database level (i.e., theappropriate

UNIQUE

statements are included in the

CREATE TABLE

statement).For convenience, unique_together can be a single tuple when dealing with a singleset of fields:

unique_together = ("driver", "restaurant")

A

ManyToManyField

cannot be included inunique_together. (It’s not clear what that would even mean!) If youneed to validate uniqueness related to a

ManyToManyField

, try using a signal oran explicit

through

model.The

ValidationError

raised during model validation when the constraintis violated has the

unique_together

error code.

今天，在家试试django的model的设置，如何设置的联合主键，我经过查资料和实践，把结果记录如下：      例如：class user(Model):
  id=AutoField(primary_key=True)
  name = CharField(max_length=30)
  age =IntegerField()
class role(Model):
  id=AutoField(primary_key=True)
  name=CharField(max_length=10)
这是两个model有一个roleUser的model来描述use与role的关系，需要user的id与role的id做外键，也做联合主键，如下：

class roleUser(Model):
userId=ForeignKey(user)
roleId=ForeignKey(role)
class Meta:
unique_together=("userId","roleId")

其中：       

class Meta:
unique_together=("userId","roleId")

就是建立联合主键。