Question

我在Django v1.6.2上运行unittest并收到此错误：

ValueError: Can't do subqueries with queries on different DBs.

但在运行网站时却没有发生。

我只指定了一个数据库。

快速搜索谷歌只找到一个相关的结果，这对我没有帮助。

更新详情：

这是管理M2M关系的中间模型，这是导致问题的查询：

ProductCategory.objects.filter(category=category, product=product).delete()

更新：添加了跟踪

======================================================================
ERROR [0.079s]: test_sync (goproducts.apps.products.tests.productSyncTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/private/var/www/goproducts/goproducts/goproducts/apps/products/tests.py", line 55, in test_sync
    product.objects.sync(self.message)
  File "/private/var/www/goproducts/goproducts/goproducts/apps/products/managers.py", line 97, in sync
    ProductCategory.objects.filter(category=category, product=product).delete()
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/query.py", line 464, in delete
    collector.collect(del_query)
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/deletion.py", line 166, in collect
    reverse_dependency=reverse_dependency)
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/deletion.py", line 77, in add
    if not objs:
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/query.py", line 100, in __nonzero__
    self._fetch_all()
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/query.py", line 854, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/query.py", line 220, in iterator
    for row in compiler.results_iter():
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 709, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 772, in execute_sql
    sql, params = self.as_sql()
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 94, in as_sql
    having, h_params = self.query.having.as_sql(qn=qn, connection=self.connection)
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/sql/where.py", line 103, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File "/private/var/www/goproducts/lib/python2.7/site-packages/django/db/models/sql/where.py", line 401, in as_sql
    raise ValueError("Can't do subqueries with queries on different DBs.")
ValueError: Can't do subqueries with queries on different DBs.

----------------------------------------------------------------------

Answer 1

我发现了问题，我使用模拟库来模拟同步功能

    Category.objects.sync = MagicMock()

对此进行了评论，修复了它。

PS，我确保我的测试没有被破坏，因为我删除了模拟。

django unittest：不能在不同的DB上查询子查询

1 个答案: