如何从Django项目（及其所有表）中删除应用

问题描述：

我想从Django项目中删除应用。

I want to remove an app from a django project.

我想删除

应用程序的表

内容类型

这些内容类型的外键用法

运行 manage.py迁移app_to_remove零不起作用：

django.db.migrations.migration.IrreversibleError: 
Operation <RunPython <function forwards_func at 0x7ff76075d668>> in
            fooapp.0007_add_bar is not reversible

我想有些迁移是不可逆的...

I guess there are several migrations which are not reversible ...

答

首先：删除代码中的引用

从设置中删除 app_to_remove 。INSTALLED_APPS

删除 urls.py 或其他位置的其他引用

First: Remove references in the code

remove app_to_remove from settings.INSTALLED_APPS
remove other references in urls.py or other places

为Django项目创建一个空迁移：

Create an empty migration for your django-project:

manage.py makemigrations your_django_project --empty

编辑文件。这是一个模板：

Edit the file. Here is a template:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

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

    operations = [
        migrations.RunSQL('''
        drop if exists table app_to_remove_table1;
        drop if exists table app_to_remove_table2;
        ....
        delete from auth_permission where content_type_id in (select id from django_content_type where app_label = '{app_label}');
        delete from django_admin_log where content_type_id in (select id from django_content_type where app_label = '{app_label}');
        delete from reversion_version where content_type_id in (select id from django_content_type where app_label = '{app_label}');
        delete from django_content_type where app_label = '{app_label}';
        delete from django_migrations where app='{app_label}';
        '''.format(app_label='app_to_remove'))
    ]

运行迁移，运行测试。

关于如果存在则删除：您有两种情况：

About "drop if exists": You have two cases:

生产系统：您要删除表。

新开发系统：这些系统从未安装过该应用，并且也没有该表格：- ）

如何从Django项目（及其所有表）中删除应用

首先：删除代码中的引用

First: Remove references in the code

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