hi all,
i have a class that have a self reference through *_parent*. this class
is mapped against an selectable, not a class (this information is
useful, lol)
ok, so, using @hybrid_property, i can easily get the amount of children
of this class:
*@hybrid_property**
**def child_count(self):**
** kls = self.__class__**
** session = object_session(self)**
** sel = select(**
** [**
** func.count(kls.id_)**
** ],**
** and_(**
** self.id_ == kls._parent,**
** or_(**
** self.language_id == kls.language_id,**
** kls.language_id.is_(sql.null())**
** )**
** )**
** )**
** return session.execute(sel).scalar()*
but, how can I transform it into an expression, so I can use it on a
query, like *session.query(cls).filter(cls.child_count == 3).all()* ? i
already did a lot of *@some_property.expression*, but I'm having a bit
of a trouble on this one :)
any help would be appreciated ...
best regards,
richard.
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