migrations.AddField( model_name='platformenv', name='tag_type', field=models.ForeignKey(blank=True, db_column='Tag_Type', null=True, on_delete=django.db.models.deletion.DO_NOTHING, to='polls.Tagtypes'), ), The DB shows the following error: Error in foreign key constraint of table ad...
0 Need to return two values from the same model to another in django 0 Django Created By and Modified By in an Abstract Base Class 2 Django: Adding 2 foreign keys referencing the same table using related_name causing NameError - value given to related name is not defined 482 Convert...
在Django中,foreign_key是一种关系字段,用于在模型之间建立关联关系。 在模板上访问通过foreign_key建立的关联数据时,可以通过以下步骤进行操作: 确保在模型中正确地定义了foreign_key字段。例如,如果一个模型A有一个foreign_key字段指向另一个模型B,那么在模型A中应该有类似于foreign_key = models.ForeignKey(...
#正向查找: boyret=models.UserInfo.objects.filter(name='liang1').first() print(boyret,'boyret---') boyret1=boyret.m.all() #通过本表的外键查询到的是 UserInfo object,如果是all() 那就是<QuerySet [<UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>]> ...
1.迁移先需要失败一次(既然出现了这个错误,说明已经迁移了一次) 2.修改当前表外键字段的字符集(或者说COLLATE),修改为外键关联表的字符集 查看表的创建语句(主要是查看外键关联表主键的字符集) SHOWCREATETABLE`user_group` (查看创建表的命令) 修改字符集 ...
Django model update foreign key 外键更新 要件: parent model: master.anken(primary key:id→anken_no) ※ id:自動生成 child model : purchase.appl migrate操作 1,parent model :执行makemigratios,migrate 2,child model :foreign key 注释掉,执行makemigratios,migrate(删掉外键)...
django.db.utils.IntegrityError: foreign key constraint failed 是一个常见的数据库错误,表明在尝试插入或更新数据库记录时违反了外键约束。这通常意味着你尝试将一条记录的外键字段设置为一个不存在的关联记录的主键。 常见原因 关联对象不存在:当你尝试插入或更新一个外键字段时,如果指定的关联对象在数据库中不存在...
I'm trying to filter by a value that is contained in a foreign key. I've seen this done in the django documentation (the blog example). Here are my models: class Students(models.Model): ssn = models.CharField(unique=True, maxlength=11) name = models.CharField(blank=True, maxlength=50...
django.db.utils.IntegrityError: (1452, 'Cannot add or update a child row: a foreign key constraint fails (`mxonline`.`django_admin_log`, CONSTRAINT `django_admin_log_user_id_c564eba6_fk_auth_user_id` FOREIGN KEY (`user_id`) REFERENCES `auth_user` (`id`))') ...
1 filter on a foreign key value django 0 Django filtering on foreign key 0 Filtering on foreign key in django Hot Network Questions How quickly could a probe reach the heliopause? Constrained optimization problem Publishing an article despite the outcomes are not what we wanted Does la...