Django“MigrationSchemaMissing：无法创建 django_migrations 表（未选择创建模式）”

Question

我正在尝试将生产数据库恢复到本地计算机，类似于 Heroku ( https://devcenter.heroku.com/articles/heroku-postgres-import-export ) 描述的工作流程。不过，我正在使用 Aptible，它为此目的提供了一个数据库隧道。

使用 pgAdmin4，我创建了一个“自定义”备份。然后，稍微修改 pgAdmin 命令，我使用以下命令恢复了它

"/Applications/pgAdmin 4.app/Contents/SharedSupport/pg_restore" --host "localhost" --port "5432" --username "postgres" --no-password --dbname "lucy_prod" --verbose "/Users/kurtpeek/lucy-prod-backup-11-june-2018" --clean

我在其中添加了--clean在重新创建数据库对象之前删除它们的选项（参见https://www.postgresql.org/docs/9.2/static/app-pgrestore.html）。

问题是，当我现在尝试时python manage.py migrate，出现以下错误：

(venv) Kurts-MacBook-Pro-2:lucy-web kurtpeek$ python manage.py migrate
Traceback (most recent call last):
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
psycopg2.ProgrammingError: no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 57, in ensure_schema
    editor.create_model(self.Migration)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 303, in create_model
    self.execute(sql, params or None)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 120, in execute
    cursor.execute(sql, params)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
django.db.utils.ProgrammingError: no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^


During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 29, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 83, in handle
    executor = MigrationExecutor(connection, self.migration_progress_callback)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/executor.py", line 20, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/loader.py", line 52, in __init__
    self.build_graph()
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/loader.py", line 209, in build_graph
    self.applied_migrations = recorder.applied_migrations()
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 65, in applied_migrations
    self.ensure_schema()
  File "/Users/kurtpeek/Documents/Dev/lucy2/lucy-web/venv/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 59, in ensure_schema
    raise MigrationSchemaMissing("Unable to create the django_migrations table (%s)" % exc)
django.db.migrations.exceptions.MigrationSchemaMissing: Unable to create the django_migrations table (no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^
)

根据我对MigrationSchemaMissing(Unable to create the django_migrations table (%s) % exc) 的理解，我需要运行

grant usage on schema public to username;
grant create on schema public to username;

但是，我应该填写什么username？应该是这样吗postgres？

public以下是有关架构和的更多详细信息search_path：

(venv) Kurts-MacBook-Pro-2:lucy-web kurtpeek$ python manage.py dbshell
psql (10.4)
Type "help" for help.

lucy_prod=> \dn+ public
                        List of schemas
  Name  |  Owner   | Access privileges |      Description       
--------+----------+-------------------+------------------------
 public | postgres |                   | standard public schema
(1 row)

lucy_prod=> SHOW search_path;
   search_path   
-----------------
 "$user", public
(1 row)

更新

通过运行select current_user;命令，我确定我当前的用户名为 name lucyapp，但如果我尝试grant usage on schema public为该用户执行此操作，则会收到“权限被拒绝”错误：

lucy_prod=> select current_user;
 current_user 
--------------
 lucyapp
(1 row)

lucy_prod=> grant usage on schema public to lucyapp;
ERROR:  permission denied for schema public
lucy_prod=> grant create on schema public to lucyapp;
ERROR:  permission denied for schema public

Answer 1

只是改变数据库所有权对我有用。

ALTER DATABASE database OWNER TO user;

Answer 2

发生这种情况是由于角色对架构的访问问题public。在数据库 shell 中运行此脚本将解决该问题。

GRANT ALL ON SCHEMA public TO your_user;
GRANT ALL ON SCHEMA public TO public;

这是针对 Postgres 数据库的。可以为其他 SQL DB 找到类似的脚本。

Answer 3

当我简单地使用命令而不是 .输入 psql 时，我就能够做到这GRANT USAGE一点。随后，我遇到了与数据库中对象的所有者（关系等）相关的错误，该错误不是设置中的所有者，即.GRANT CREATEpsqlpython manage.py dbshellDATABASES['USER']'lucyapp'

pg_restore我终于使用--no-owner和选项解决了问题--role=lucyapp，遵循Postgresql - 备份数据库并在不同所有者上恢复？。