Question

从模型中删除属性（sqlite3）后：

class Course(models.Model):
    Name = models.CharField(max_length=30,unique=True)
    Active = models.BooleanField(default=True)
#    rubric = models.ForeignKey(Rubric) #removed attribute

    def __unicode__(self):
        return u'%s' % (self.Name)

使用migrate时出错（makemigrations很好）：

django.db.utils.IntegrityError: NOT NULL constraint failed: gbook_course.rubric_id

此字段不再存在！我不明白这是失败的地方，或者在哪里修复它。重新添加属性并使用null=True, blank=True并将属性更改为CharField或其他类型也无法解决问题。

从sqlite命令行应用程序打开数据库并查看课程表的模式，我得到那里没有标记字段的指示：

CREATE TABLE "gbook_course" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "Active" bool NOT NULL, "Name" varchar(30) NOT NULL UNIQUE);

在一个相关的说明中，我认为可能我刚刚开始使用数据库，因此我也尝试删除它和应用程序的迁移（__init__.py除外），这应该从从头开始，我最终得到了来自runserver和迁移的错误：

django.db.utils.OperationalError: no such table: gbook_student

此时，没有DB存在（完全删除），所以我真的不确定这个错误可能来自哪里。这两个问题的解决方案都很好 - 如果需要，我可以重新启动空白数据库。

迁移追溯：

ltjgates:gbsite jgates$ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, gbook, sessions
Running migrations:
  Rendering model states... DONE
  Applying gbook.0011_course_rubric...Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 359, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 305, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 356, in execute
    output = self.handle(*args, **options)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 202, in handle
    targets, plan, fake=fake, fake_initial=fake_initial
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in migrate
    state = self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/migrations/executor.py", line 132, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/migrations/executor.py", line 237, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/migrations/migration.py", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 84, in database_forwards
    field,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/schema.py", line 231, in add_field
    self._remake_table(model, create_fields=[field])
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/schema.py", line 199, in _remake_table
    self.quote_name(model._meta.db_table),
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 112, in execute
    cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 337, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: NOT NULL constraint failed: gbook_course.rubric_id

已删除数据库追踪（makemigrations）：

ltjgates:gbsite jgates$ python manage.py makemigrations
Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 359, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 305, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 353, in execute
    self.check()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 385, in check
    include_deployment_checks=include_deployment_checks,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 372, in _run_checks
    return checks.run_checks(**kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/checks/registry.py", line 81, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/checks/urls.py", line 14, in check_url_config
    return check_resolver(resolver)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/checks/urls.py", line 24, in check_resolver
    for pattern in resolver.url_patterns:
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/urls/resolvers.py", line 310, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/urls/resolvers.py", line 303, in urlconf_module
    return import_module(self.urlconf_name)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbsite/urls.py", line 21, in <module>
    url(r'^gbook/', include('gbook.urls')),
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/conf/urls/__init__.py", line 50, in include
    urlconf_module = import_module(urlconf_module)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbook/urls.py", line 2, in <module>
    from . import views
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbook/views.py", line 12, in <module>
    from gbook.forms import *
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbook/forms.py", line 38, in <module>
    class StudentChooseForm(forms.ModelForm):
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbook/forms.py", line 39, in StudentChooseForm
    class Meta:
  File "/Volumes/ProfileHD/jgates/Desktop/Gbook/gbsite/gbook/forms.py", line 45, in Meta
    'Email': CheckboxSelectMultiple(choices=( (x.id, x.FirstName+" "+x.LastName) for x in CHOICES )),
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 256, in __iter__
    self._fetch_all()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 1085, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 54, in __iter__
    results = compiler.execute_sql()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 835, in execute_sql
    cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 337, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: gbook_student

Answer 1

仍然不确定确切原因，但这有效（在SQLite命令行工具中）：

sqlite> select * from gbook_course;
1|1|Honors Physics
2|1|Physics
3|1|AP Physics
sqlite> delete from gbook_course;

现在架构显示为：

CREATE TABLE "gbook_course" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "Name" varchar(30) NOT NULL UNIQUE, "Active" bool NOT NULL, "rubric_id" integer NULL REFERENCES "gbook_rubric" ("id"));
CREATE INDEX "gbook_course_8980b7ae" ON "gbook_course" ("rubric_id");

Django数据库迁移问题：不存在的属性

1 个答案: