如何伪造迁移以便不创建特定的现有中间表

Question

我有以下型号

class VucutBolgesi(models.Model):
    site = models.ForeignKey(Site)
    bolge = models.CharField(verbose_name="Bölge", max_length=75)
    hareketler = models.ManyToManyField("Hareket", verbose_name="Hareketler", null=True, blank=True, help_text="Bölgeyi çal??t?ran hareketler")


class Hareket(models.Model):
    site = models.ForeignKey(Site)
    hareket = models.CharField(verbose_name="Hareket", max_length=75 )
    bolgeler = models.ManyToManyField(VucutBolgesi, verbose_name="Çal??t?rd??? Bölgeler", null=True, blank=True,
                                      help_text="Hareketin çal??t?rd??? bölgeler")

我在两个表上都有相同的M2M,因为我希望在两个管理表单上显示相同的中间表.他们还必须使用相同的表(不创建两个单独的表),因为一个管理表单中的一个更改必须反映到另一个.就像,如果我添加一个新的Hareket来VucutBolgesi过HareketAdmin,然后同样的结果shoudl上看到VucutBolgesiAdmin过.

为了实现这一点,我首先删除hareketlerM2M字段,VucutBolgesi因此Hareketler模型将创建中间表.我这个迁移,然后添加hareketler到VucutBolgesi与db_table属性,这样它会识别同一中介表.

该领域的最终外观如下

hareketler = models.ManyToManyField("Hareket", verbose_name="Hareketler", db_table="antrenman_hareket_bolgeler",
                                    null=True, blank=True, help_text="Bölgeyi çal??t?ran hareketler")

当我尝试迁移它时,django会抛出异常

django.db.utils.OperationalError: table "antrenman_hareket_bolgeler" already exists

我应该如何伪造这种迁移？

以下是每次运行时django创建的迁移 makemigrations

dependencies = [
    ('antrenman', '0005_vucutbolgesi_hareketler'),
]

operations = [
    migrations.AddField(
        model_name='vucutbolgesi',
        name='hareketler',
        field=models.ManyToManyField(to='antrenman.Hareket', db_table=b'antrenman_hareket_bolgeler', blank=True, help_text=b'B\xc3\xb6lgeyi \xc3\xa7al\xc4\xb1\xc5\x9ft\xc4\xb1ran hareketler', null=True, verbose_name=b'Hareketler'),
        preserve_default=True,
    ),
]

注意:编辑相关的迁移文件并删除migrations.AddField不起作用,因为django会为migrations.AddField每个创建相同的内容makemigrations

Answer 1

是否可以使迁移总是伪造,只需覆盖apply和unapply方法.对此的后果没有得到充分的研究,但这对我来说很有用.

在以下示例中,我们创建了一个重用django.contrib.auth.User.groupM2M表的迁移b'profile_user_groups:

from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('profile', '0001_initial'),
    ]

    operations = [
        migrations.AddField(
            model_name='user',
            name='organizations',
            field=models.ManyToManyField(db_column=b'group_id', db_table=b'profile_user_groups', related_name='members', to='profile.Organization'),
        ),
    ]

    def apply(self, project_state, schema_editor, collect_sql=False):
        return project_state.clone()

    def unapply(self, project_state, schema_editor, collect_sql=False):
        return project_state.clone()