Question

我尝试使用postgresql数据库（在我有SQLite之前），但是当我执行python manage.py migrate时我收到一条消息：

Operations to perform:
Apply all migrations: sessions, admin, sites, auth, contenttypes, main_app
Running migrations:
Rendering model states... DONE
Applying main_app.0004_auto_20161002_0034...Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 345, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 348, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 399, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 200, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 92, in migrate
self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 121, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 198, in apply_migration
state = migration.apply(state, schema_editor)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 123, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 201, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 482, in alter_field
old_db_params, new_db_params, strict)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/postgresql/schema.py", line 110, in _alter_field
new_db_params, strict,
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 634, in _alter_field
params,
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 110, in execute
cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 95, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: column "id" does not exist
LINE 1: ..._app_projet" ALTER COLUMN "id" TYPE integer USING "id"::inte...

所以我猜这个错误是关于我的模型＆＃39; Projet＆＃39;但这个型号有ID字段！我在 0001_initial.py ：

中看到了这一点

...
migrations.CreateModel(
        name='Projet',
        fields=[
            ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
            ('name', models.CharField(db_index=True, max_length=30)),
            ('presentation', models.TextField(max_length=2500, null=True)),
...

我的迁移main_app.0004_auto_20161002_0034：

class Migration(migrations.Migration):

    dependencies = [
        ('main_app', '0003_auto_20161002_0033'),
    ]

    operations = [
        migrations.AlterField(
            model_name='projet',
            name='id',
            field=models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID'),
    ),
    ]

Projet模型就是这样：

class Group(models.Model) :
    name = models.CharField(max_length=30, db_index=True)

    class Meta :
        abstract = True
        unique_together = (("id", "name"),)


class Projet(Group) :
    presentation = models.TextField(max_length=2500, null=True)

真的，我不明白为什么会出现这个错误...我的设置配置数据库很好，所有其他模型都有效，...

如果我忘记了什么，请不要犹豫告诉我！我需要你的帮助！

Answer 1

您的模型定义并未将任何字段标识为主键，因此Django会假定名为id的主键列。但是，该列实际上并未存在于表中。

更改模型定义以将其中一个字段指定为主键，Django不会尝试查找id列。

Answer 2

class Group(models.Model) :
    name = models.CharField(max_length=30, unique=True)

    class Meta:
        abstract = True


class Projet(Group) :
    presentation = models.CharField(max_length=2500, blank=True)

删除迁移并创建一个新迁移。

加我的两分钱。

可空字段：

避免在基于字符串的字段（如CharField和）上使用null   TextField，因为空字符串值将始终存储为空   字符串，而不是NULL。如果基于字符串的字段具有null = True，那么   意味着它有两个可能的“无数据”值：NULL，空   串。在大多数情况下，拥有两个可能的值是多余的   “没有数据;”Django约定是使用空字符串，而不是NULL。

请参阅https://docs.djangoproject.com/en/1.10/ref/models/fields/#null

MAX_LENGTH：

如果指定max_length属性，它将反映在   自动生成的表单字段的Textarea小部件。但事实并非如此   在模型或数据库级别强制执行。使用CharField。

https://docs.djangoproject.com/en/1.10/ref/models/fields/#textfield

Answer 3

如果缺少id列，只需在Postgres本身中添加该列。转到pgadmin而不是表，然后在其中创建列ID。

比起回溯到Django makemigrations更重要。如果失败，请删除应用程序迁移文件夹中的所有内容，而不使用 init .py并删除文件夹中的所有内容 pycache

先进行makemigrations再进行迁移，它应该可以工作。

Answer 4

这样做：

您需要从数据库中删除该表。
```
DROP TABLE <table>;
```
执行迁移：
```
python manage.py migrate
```

如果这没有帮助，请使用 peewee 进行迁移：

/var/venv3.8/bin/pw_migrate migrate --database=postgresql://postgres@127.0.0.1:5432/<db>

Django：ProgrammingError：column＆＃34; id＆＃34;不存在

4 个答案: