Django: 无法获取Bugzilla中的Flag信息

我在开发一个Django应用来从Bugzilla数据库中拉取数据，在获取Bug标记信息时遇到了问题。

模型定义:

class Bugzilla_bugs(models.Model):
    class Meta:
        db_table = 'bugs'

    bug_id = models.IntegerField(primary_key=True)
    ...         

class Bugzilla_flagtypes(models.Model):
    class Meta:
        db_table = 'flagtypes'

    name = models.CharField(max_length=50,unique=True)
    description = models.TextField()
    ...

class Bugzilla_flags(models.Model):
    class Meta:
        db_table = 'flags'

    type_id = models.ForeignKey(Bugzilla_flagtypes,related_name='flagtype',db_column='type_id',to_field='name')
    status = models.CharField(max_length=50)
    bug_id = models.ForeignKey(Bugzilla_bugs,related_name='flaglines',db_column='bug_id',to_field='bug_id')

当我想获取特定Bug的标记线时，会出现异常：

bug = Bugzilla_bugs.objects.using('bugzilla').get(bug_id=12345)
bug.flaglines.get(type_id="UnlocksBranch")

# 输出:
>>> bug.flaglines.get(type_id__name="UnlocksBranch")
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 92, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 351, in get
    num = len(clone)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 122, in __len__
    self._fetch_all()
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 966, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 265, in iterator
    for row in compiler.results_iter():
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 700, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 786, in execute_sql
    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/backends/mysql/base.py", line 128, in execute
    return self.cursor.execute(query, args)
  File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 176, in execute
    if not self._defer_warnings: self._warning_check()
  File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 92, in _warning_check
    warn(w[-1], self.Warning, 3)
Warning: Incorrect integer value: 'UnlocksBranch' for column 'type_id' at row 1

解决方案

问题的原因在于Bugzilla_flags模型中的type_id字段与数据库中的type_id列不匹配。

在数据库中，type_id列存储的是整型主键，但是在模型中，type_id字段却被定义为外键，并且指定了to_field='name', 这就导致了Django在检索数据时无法正确匹配。

要解决这个问题，需要将Bugzilla_flags模型中的type_id字段定义为整型字段，并移除to_field参数。

修改后的模型定义如下：

class Bugzilla_flags(models.Model):
    class Meta:
        db_table = 'flags'

    type_id = models.IntegerField(db_column='type_id')
    status = models.CharField(max_length=50)
    bug_id = models.ForeignKey(Bugzilla_bugs,related_name='flaglines',db_column='bug_id',to_field='bug_id')

修改后，就可以正确检索数据了。