在django中使用元类

Question

Can someone please explain why is meta class used in the following example.

Ex:

Class Employee (models.Model):
    name = models.ForeignKey(name)
    Gender = models.IntegerField()


    class Meta:
        ordering = ["Gender"]

Thanks.

Answer 1

Django models use the Meta class to contain extra information about the model that would not necessarily be appropriate to contain within the model class itself. Note that this is not the same as Python's metaclass ; that is a completely different topic.

In this case it ordering or sorting the queries to this model by field "Gender"

Answer 2

因为作者/程序员想要按性别字段的值对结果进行排序。

Answer 3

在这种情况下，如果您未在查询中提供ORDER_BY ，它将定义用于排序的默认字段。

Answer 4

It is explained in Django Documentation for Models

https://docs.djangoproject.com/en/dev/topics/db/models/

Give your model metadata by using an inner class Meta, like:

Class Employee (models.Model):
    ....

    class Meta:
        ordering = ["attribute-X"]

Another useful option can be used in class Meta is verbose_name.