IntegrityError: null value in column "id" for all models/fields with ForeignKey after postgres restore from dump

Question

我运行遇到问题，试图从我拥有的本地 postgres 数据库的恢复中使用 heroku postgres 数据存储。使用恢复后的 postgres 数据库 Django 正常运行。它检索所有对象并使用它们的字段、主键等，没有任何问题。

但是当涉及到写入数据库时，无论型号如何，我都会遇到同样的错误。

psycopg2.IntegrityError: null value in column "id" violates not-null constraint

当我重置 heroku 数据库并从空白板创建对象时，没有任何问题。但是如果我尝试在恢复的数据库上创建任何对象，我总是得到这个 null value in column "id" violates not-null constraint

这里是 copy/pasted 尝试在 Django Admin 中创建基本模型的堆栈跟踪。我选择这个模型示例是因为没有与创建它相关的额外代码。没有信号或任何东西。

Django Version: 2.0 Python Version: 3.6.3

Traceback:

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute 85. return self.cursor.execute(sql, params)

The above exception (null value in column "id" violates not-null constraint DETAIL: Failing row contains (null, Special Class, special-class). ) was the direct cause of the following exception:

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner 35. response = get_response(request)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response 128. response = self.process_exception_by_middleware(e, request)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response 126. response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/options.py" in wrapper 574. return self.admin_site.admin_view(view)(*args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/decorators.py" in _wrapped_view 142. response = view_func(request, *args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/views/decorators/cache.py" in _wrapped_view_func 44. response = view_func(request, *args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/sites.py" in inner 223. return view(request, *args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/options.py" in add_view 1553. return self.changeform_view(request, None, form_url, extra_context)

File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/decorators.py" in _wrapper 62. return bound_func(*args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/decorators.py" in _wrapped_view 142. response = view_func(request, *args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/decorators.py" in bound_func 58. return func.get(self, type(self))(*args2, **kwargs2)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/options.py" in changeform_view 1450. return self._changeform_view(request, object_id, form_url, extra_context)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/options.py" in _changeform_view 1490. self.save_model(request, new_object, form, not add)

File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/options.py" in save_model 1026. obj.save()

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py" in save 729. force_update=force_update, update_fields=update_fields)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py" in save_base 759. updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py" in _save_table 842. result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py" in _do_insert 880. using=using, raw=raw)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/manager.py" in manager_method 82. return getattr(self.get_queryset(), name)(*args, **kwargs)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/query.py" in _insert 1125. return query.get_compiler(using=using).execute_sql(return_id)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in execute_sql 1280. cursor.execute(sql, params)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in execute 100. return super().execute(sql, params)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in execute 68. return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute_with_wrappers 77. return executor(sql, params, many, context)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute 85. return self.cursor.execute(sql, params)

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/utils.py" in exit 89. raise dj_exc_value.with_traceback(traceback) from exc_value

File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute 85. return self.cursor.execute(sql, params)

Exception Type: IntegrityError at /admin/fantasy/raceclass/add/ Exception Value: null value in column "id" violates not-null constraint DETAIL: Failing row contains (null, Special Class, special-class).

来自堆栈跟踪的模型（请记住，这个错误会发生在每个模型上，而不仅仅是这个[非常基本的]模型。）

class RaceClass(models.Model):
    title = models.CharField(max_length=140)
    slug = models.SlugField(unique=True)

    def __str__(self):
        return self.title

    class Meta:
        ordering = ['title']

以下是我将本地数据恢复（d）到 heroku 的方法：

我正在使用命令转储我的本地 Postgres 数据库（版本 10.0）：

PGPASSWORD=mypassword pg_dump -Fc --no-acl --no-owner -h localhost -U myuser mydb > mydb.dump

然后上传到 AWS，并使用命令恢复到 Heroku 上的 Postgres 数据存储（版本 9.6.5）：

heroku pg:backups:restore 'https://s3.amazonaws.com/me/items/3H0q/mydb.dump' DATABASE_URL

这些都直接来自 Heroku 文档：https://devcenter.heroku.com/articles/heroku-postgres-import-export

旁注：我在本地使用 10.0 版 Postgres，Heroku Datastore 是 9.6.5

Answer 1

我相当确定这是因为您正在从 Postgres 10 导出并导入到 9。它并没有完全失败，但是一些模式定义（在本例中是自动递增的 ID 字段）没有正在正确导入。

我能想到两个方案：

尝试转储原始 SQL 而不是自定义格式：
```
PGPASSWORD=mypassword pg_dump --no-acl --no-owner -h localhost -U myuser mydb > mydb.sql
```
您不能使用 pg_restore 加载它 - 您必须使用 psql 手动运行查询。这样的事情应该有效：
```
heroku pg:psql < mydb.sql
```
这里需要注意的是，您首先需要清空现有数据库。
如果这也失败，那么您需要从您要导入到的相同主版本的 Postgres 中导出。

Answer 2

关键错误是这样的：

I'm using Version 10.0 Postgres locally and Heroku Datastore is 9.6.5

这是一个等待发生的问题。我会尝试在两者上使用相同的版本。至少相同的主要版本。

特别想到这两个的是标准-SQL IDENTITY columns in Postgres 10 的引入，这主要是为了取代串行列。你没有透露 table 定义，所以我只能猜测。 Postgres 10 中的 IDENTITY 功能不会转换回 Postgres 9.6，这可以很好地解释错误消息中违反 NULL 值的原因。

IntegrityError: null value in column "id" for all models/fields with ForeignKey after postgres restore from dump

IntegrityError: null value in column "id" for all models/fields with ForeignKey after postgres restore from dump

django

postgresql

heroku

django-migrations

django-2.0