Specify a custom query class

[immunda]

Devise a cohesive way to be able to provide a custom query class, which would be used for Model.query_class, session as qry_class, be set for db.Query, be used for db.relationship and db.backref. Essentially everywhere BaseQuery is used.

Thanks to the contributions and discussion from @justanr, @davidism & @RonnyPfannschmidt.

[RonnyPfannschmidt]

i dont see why #263 was not merged tho,

the next step would be to have a query_base parameter to init i suppose,

#263 was about db.session.query using a different query class than flask-sqlalchemy to begin with

[immunda]

Because I would prefer to pass it as an arg to the constructor and have that be reflected throughout, rather than accept it as part of sesssion_options and then change the API a second time.

[justanr]

Doing this properly will require passing the custom query class all the way down to _set_default_query_class, including _wrap_with_default_query_class and _include_sqlalchemy. Otherwise some queries will have the new query class and some will have the BaseQuery class.

The other issue is by default flask_sqlalchemy.Model declares query_class = BaseQuery explicitly. The only good work around is doing something like this in SQLAlchemy.__init__:

class SQLAlchemy(object):
     # may as well provide for custom base models as well
     # makes building something like SurrogatePKMixin easier
    def __init__(self, query_class=BaseQuery, model_class=Model, **others):
        self.Model = self.make_declarative_base(metadata, model_class)
        # not crazy about this part
        self.Model.query_class = query_class
        self.Query = query_class

[traut]

is that the last fix required for milestone 2.1?

[immunda]

Resolved in #328