<p>如果我理解正确,您需要所有非活动对象对查询不可见。以下类将筛选出<code>active</code>属性设置为<code>False</code>的所有模型对象,包括通过关系访问的对象:</p>
<pre><code>from sqlalchemy.orm import Query
from sqlalchemy.orm.util import _class_to_mapper
class QueryActive(Query):
def __init__(self, entities, *args, **kwargs):
Query.__init__(self, entities, *args, **kwargs)
query = self
for entity in entities:
if hasattr(entity, 'parententity'):
entity = entity.parententity
cls = _class_to_mapper(entity).class_
if hasattr(cls, 'active'):
query = query.filter(cls.active==True)
self._criterion = query._criterion
def get(self, ident):
# Use default implementation when there is no condition
if not self._criterion:
return Query.get(self, ident)
# Copied from Query implementation with some changes.
if hasattr(ident, '__composite_values__'):
ident = ident.__composite_values__()
mapper = self._only_mapper_zero(
"get() can only be used against a single mapped class.")
key = mapper.identity_key_from_primary_key(ident)
if ident is None:
if key is not None:
ident = key[1]
else:
from sqlalchemy import util
ident = util.to_list(ident)
if ident is not None:
columns = list(mapper.primary_key)
if len(columns)!=len(ident):
raise TypeError("Number of values doesn't match number "
'of columns in primary key')
params = {}
for column, value in zip(columns, ident):
params[column.key] = value
return self.filter_by(**params).first()
</code></pre>
<p>要使用它,您必须创建一个单独的会话对象:</p>
^{pr2}$
<p>这种方法有局限性,对于一些复杂的查询来说不适用,但对于大多数项目来说是可以的。在</p>