Python django.db.utils.IntegrityError:(1062,“重复输入”用于键和段塞
我正试图学习tangowithdjango的书,必须添加一个slug来更新category表。但是,在尝试迁移数据库之后,我遇到了一个错误 我没有为slug提供默认值,因此Django要求我提供一个默认值,并按照书中的指示键入“” 值得注意的是,我使用的不是像原著中那样使用sqlite,而是mysqlPython django.db.utils.IntegrityError:(1062,“重复输入”用于键和段塞,python,mysql,django,django-1.7,Python,Mysql,Django,Django 1.7,我正试图学习tangowithdjango的书,必须添加一个slug来更新category表。但是,在尝试迁移数据库之后,我遇到了一个错误 我没有为slug提供默认值,因此Django要求我提供一个默认值,并按照书中的指示键入“” 值得注意的是,我使用的不是像原著中那样使用sqlite,而是mysql models.py from django.db import models from django.template.defaultfilters import slugify # Crea
models.py
from django.db import models
from django.template.defaultfilters import slugify
# Create your models here.
class Category(models.Model):
name = models.CharField(max_length=128, unique=True)
views = models.IntegerField(default=0)
likes = models.IntegerField(default=0)
slug = models.SlugField(unique=True)
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Category, self).save(*args, **kwargs)
class Meta:
verbose_name_plural = "Categories"
def __unicode__(self):
return self.name
class Page(models.Model):
category = models.ForeignKey(Category)
title = models.CharField(max_length=128)
url = models.URLField()
views = models.IntegerField(default=0)
def __unicode__(self):
return self.title
命令提示符
sudo python manage.py migrate
Operations to perform:
Apply all migrations: admin, rango, contenttypes, auth, sessions
Running migrations:
Applying rango.0003_category_slug...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 385, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 377, 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 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 160, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 63, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 97, in apply_migration
migration.apply(project_state, schema_editor)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 37, in database_forwards
field,
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/schema.py", line 42, in add_field
super(DatabaseSchemaEditor, self).add_field(model, field)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/schema.py", line 411, in add_field
self.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/schema.py", line 98, in execute
cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 94, 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 65, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/base.py", line 128, in execute
return self.cursor.execute(query, args)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
django.db.utils.IntegrityError: (1062, "Duplicate entry '' for key 'slug'")
sudo python manage.py迁移
要执行的操作:
应用所有迁移:admin、rango、contenttypes、auth、sessions
运行迁移:
正在应用rango.0003\u类别\u slug…回溯(最近一次调用):
文件“manage.py”,第10行,在
从命令行(sys.argv)执行命令
文件“/usr/local/lib/python2.7/dist-packages/django/core/management/__-init__;.py”,第385行,从命令行执行
utility.execute()
文件“/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py”,第377行,在execute中
self.fetch_命令(子命令)。从_argv(self.argv)运行_
文件“/usr/local/lib/python2.7/dist-packages/django/core/management/base.py”,第288行,在运行中,从
self.execute(*args,**选项._dict__;
文件“/usr/local/lib/python2.7/dist packages/django/core/management/base.py”,第338行,在execute中
输出=self.handle(*args,**选项)
handle中的文件“/usr/local/lib/python2.7/dist packages/django/core/management/commands/migrate.py”,第160行
executor.migrate(目标、计划、假=options.get(“假”,假))
文件“/usr/local/lib/python2.7/dist packages/django/db/migrations/executor.py”,第63行,在migrate中
self.apply\u迁移(迁移,假=假)
文件“/usr/local/lib/python2.7/dist packages/django/db/migrations/executor.py”,第97行,在apply_migration中
应用(项目状态,模式编辑器)
文件“/usr/local/lib/python2.7/dist packages/django/db/migrations/migration.py”,第107行,在apply中
数据库转发(self.app\u标签、模式编辑器、项目状态、新状态)
数据库中的文件“/usr/local/lib/python2.7/dist packages/django/db/migrations/operations/fields.py”,第37行
领域
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/mysql/schema.py”,第42行,在add_字段中
super(DatabaseSchemaEditor,self).add_字段(model,field)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/schema.py”,第411行,在add_字段中
self.execute(sql,params)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/schema.py”,执行中的第98行
cursor.execute(sql,params)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/utils.py”,执行中的第81行
返回super(CursorDebugWrapper,self).execute(sql,params)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/utils.py”,执行中的第65行
返回self.cursor.execute(sql,params)
文件“/usr/local/lib/python2.7/dist packages/django/db/utils.py”,第94行,在__
6.重新播放(dj_exc_类型、dj_exc_值、回溯)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/utils.py”,执行中的第65行
返回self.cursor.execute(sql,params)
文件“/usr/local/lib/python2.7/dist packages/django/db/backends/mysql/base.py”,执行中的第128行
返回self.cursor.execute(查询,参数)
文件“/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py”,执行中的第205行
errorhandler(self、exc、value)
defaulterrorhandler中的文件“/usr/local/lib/python2.7/dist packages/MySQLdb/connections.py”,第36行
提高errorclass,errorvalue
django.db.utils.IntegrityError:(1062,“键“slug”的重复条目”)
表中的行必须已经有空段塞,这违反了您创建的mysql唯一约束。您可以手动更新它们,方法是运行manage.py dbshell
访问mysql客户端,然后更新有问题的行,例如
updatetable rango\u category set slug=name,其中slug=''代码>
(假设具有空白段塞的行具有名称)。或者,您可以使用删除行
从rango_类别中删除,其中slug=''代码>
之后,您应该能够运行迁移。让我们一步一步地分析它:
您正在使用unique=True
添加slug
字段,这意味着:每个记录必须有不同的值,在slug
中不能有两个值相同的记录
您正在创建迁移:django要求您为数据库中已经存在的字段提供默认值,所以您提供了“”(空字符串)作为该值
现在django正在尝试迁移您的数据库。在数据库中,我们至少有2条记录
迁移第一条记录,用空字符串填充slug列。这很好,因为没有其他记录在slug
字段中有空字符串
迁移第二条记录,用空字符串填充slug列。这失败了,因为第一条记录在slug
字段中已经有空字符串。引发异常并中止迁移
这就是迁移失败的原因。您所要做的就是编辑迁移,复制迁移。AlterField
操作两次,在第一次操作中remove unique=True。在这两个操作之间,您应该放置migrations.RunPython
操作,并在其中提供两个参数:generate\u slug
和migrations.RunPython.noop
现在,您必须在迁移类之前在迁移函数内部创建,将该函数命名为generate\u slug
。函数应该有两个参数:apps
和schema\u编辑器
。在函数的第一行:
Category = apps.get_model('your_app_name', 'Category')
现在使用Category.objects.all()
循环所有记录,并为每个记录提供唯一的slug。如果表中有多个类别,则不能使用unique=True
和default='
,因为