IntegrityError：（1062，“Duplicate entry”1830327-1792993“，用于密钥”some_instance_A_id“），但没有UNIQUE约束

问题描述

我很少将模型实例添加到many2many字段时会得到这样的异常，例如：

I'm rarely getting such exception when adding model instance to many2many field, i.e.:

 some_instance_A.my_m2m.add(some_instance_B)). 

它的工作原理是99/100次。对我来说看起来很奇怪，就是这个破折号 - 主键是整数..

It works say 99/100 times. What looks strange to me, is that dash sign - as primary keys are integers..

模型字段定义如下：

 my_m2m = ManyToManyField(B)

so这是最简单的M2M定义可能

so it's the simplest M2M definition possible

完全追溯（轻微编辑以保护隐私））：

Full traceback (with minor edits to protect privacy :)):

File "*******", line 278, in process_request
   some_instance_A.my_m2m.add(some_instance_B)
 File "/var/lib/python-support/python2.5/django/db/models/fields/related.py", line 490, in add
   self._add_items(self.source_field_name, self.target_field_name, *objs)
 File "/var/lib/python-support/python2.5/django/db/models/fields/related.py", line 574, in _add_items
   '%s_id' % target_field_name: obj_id,
 File "/var/lib/python-support/python2.5/django/db/models/query.py", line 352, in create
   obj.save(force_insert=True, using=self.db)
 File "/var/lib/python-support/python2.5/django/db/models/base.py", line 435, in save
 self.save_base(using=using, force_insert=force_insert, force_update=force_update)
 File "/var/lib/python-support/python2.5/django/db/models/base.py", line 528, in save_base
 result = manager._insert(values, return_id=update_pk, using=using)
 File "/var/lib/python-support/python2.5/django/db/models/manager.py", line 195, in _insert
 return insert_query(self.model, values, **kwargs)
 File "/var/lib/python-support/python2.5/django/db/models/query.py", line 1479, in insert_query
 return query.get_compiler(using=using).execute_sql(return_id)
 File "/var/lib/python-support/python2.5/django/db/models/sql/compiler.py", line 783, in execute_sql
 cursor = super(SQLInsertCompiler, self).execute_sql(None)
 File "/var/lib/python-support/python2.5/django/db/models/sql/compiler.py", line 727, in execute_sql
 cursor.execute(sql, params)
 File "/var/lib/python-support/python2.5/django/db/backends/mysql/base.py", line 86, in execute
 return self.cursor.execute(query, args)
 File "/var/lib/python-support/python2.5/MySQLdb/cursors.py", line 166, in execute
 self.errorhandler(self, exc, value)
 File "/var/lib/python-support/python2.5/MySQLdb/connections.py", line 35, in defaulterrorhandler
 raise errorclass, errorvalue
 IntegrityError: (1062, "Duplicate entry '1830327-1792993' for key 'some_instance_A_id'")

推荐答案

您可以发布产生此结果的代码片段吗？

Can you post the code snippet that yields this result?

至少在Postgres上，如果您尝试在事务中保存两次实例，则可能会发生这种情况。

At least on Postgres this can happen if you try saving an instance twice inside a transaction.

这篇关于IntegrityError：（1062，“Duplicate entry”1830327-1792993“，用于密钥”some_instance_A_id“），但没有UNIQUE约束的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！