我想从
django项目中删除一个应用程序.
我想删除
运行manage.py migrate 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
我想有几次迁移是不可逆的……
解决方法
第一：删除代码中的引用
>从settings.INSTALLED_APPS中删除app_to_remove
>删除urls.py或其他地方的其他引用
第二：清理数据库
为您的django项目创建一个空迁移：
manage.py makemigrations your_django_project --empty
编辑文件.这是一个模板：
# -*- 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“drop if exists”：你有两种情况：
>生产系统：您想放弃表格.>新的开发系统：这些系统从来没有这个应用程序,他们没有这个表:-)