django.db.utils.DatabaseError错误

Question

我正在设置一个Django模型，用来存储地区，比如美国、德国等等。我把地区名称设定为在表中唯一，也就是说不能有重复的名字。我有一个脚本可以从一个列表中填充数据库，如果出现重复的地区名称，就会像预期那样抛出一个完整性错误（IntegrityError），但接着又出现了另一个错误，我从错误信息中看不出原因。有没有什么想法？谢谢！

django.db.utils.DatabaseError: current transaction is aborted, commands ignored until end of transaction block

模型：

class Region(models.Model):
    name = models.CharField(max_length=512, unique=True)

    def __unicode__(self):
        return self.name

填充代码：

    try:
        Region(name=server['locale']).save()
        print 'Added region: %(locale)s' % server
    except IntegrityError:
        pass

我确认了完整性错误确实发生了，但随后我得到了一个我没预料到的错误：

  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/base.py", line 456, in save
    self.save_base(using=using, force_insert=force_insert, force_update=force_update)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/base.py", line 549, in save_base
    result = manager._insert(values, return_id=update_pk, using=using)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/manager.py", line 195, in _insert
    return insert_query(self.model, values, **kwargs)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/query.py", line 1518, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/sql/compiler.py", line 788, in execute_sql
    cursor = super(SQLInsertCompiler, self).execute_sql(None)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/models/sql/compiler.py", line 732, in execute_sql
    cursor.execute(sql, params)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/backends/util.py", line 15, in execute
    return self.cursor.execute(sql, params)
  File "/home/daedalus/webapps/wowstatus/lib/python2.6/django/db/backends/postgresql_psycopg2/base.py", line 44, in execute
    return self.cursor.execute(query, args)
django.db.utils.DatabaseError: current transaction is aborted, commands ignored until end of transaction block

Answer 1

我在使用Django命令行访问数据库时，有时候会遇到这个错误。解决这个问题的方法是关闭连接：

from django.db import connection
connection.close()
cur = connection.cursor()
sql = 'select distinct category from uploads_document'
cur.execute(sql)

这个错误通常是在我写错查询，比如写成了'select ditsinct ..'之后出现的。

Answer 2

如果发生错误，你应该重置你的数据库状态。举个例子：

from django.db import transaction

@transaction.commit_manually
def Populate():
    try:
        Region(name=server['locale']).save()
        print 'Added region: %(locale)s' % server
    except IntegrityError:
        transaction.rollback()
    else:
        transaction.commit()