Python-сообщество

db.session.remove()
db.session = scoped_session(sessionmaker(bind=engine))

AttributeError: 'NoneType' object has no attribute 'query'
File "C:\Python27\lib\site-packages\flask_admin\contrib\sqla\view.py", line 606, in get_query
return self.session.query(self.model)

 connection = engine.connect()
    result = connection.execute("select count(*) from base.objecttype")
    for row in result:
        print row

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker, create_session
engine = None
db_session = scoped_session(lambda: create_session(bind=engine))
from flask.ext.sqlalchemy import SQLAlchemy
db = SQLAlchemy()
def init_engine(**kwargs):
    global engine
    global db_session
    global db
    SQLALCHEMY_DATABASE_URI = "postgresql://postgres:passs@%s/master" % session['db']
    print SQLALCHEMY_DATABASE_URI
    engine = create_engine(SQLALCHEMY_DATABASE_URI, convert_unicode=True, echo=True, **kwargs)
    db.session.remove()
    db.session = db_session
    #scoped_session(sessionmaker(bind=engine))
    session['db_state'] = True
    connection = engine.connect()
    result = connection.execute("select count(*) from base.objecttype")
    for row in result:
        print row

@app.route('/connect')
def connect():
    session['db'] = request.args.get('host', '127.0.0.1')
    session['db_state'] = False
    init_engine()
    return redirect('/admin')
if __name__ == '__main__':
    admin = Admin(app, index_view=Connect_View(name='БД'))
    from flask.ext.admin.contrib.sqla import ModelView
    from ot_model import ObjectTypeModel
    admin.add_view(ModelView(ObjectTypeModel, db_session))

from config import db
class ObjectTypeModel(db.Model):
    __tablename__ = "base.objecttype"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, unique=True)
    comment = db.Column(db.String)

ProgrammingError: (ProgrammingError) ОШИБКА: отношение "base.objecttype" не существует LINE 2: FROM "base.objecttype" ^ 'SELECT count(%(param_1)s) AS count_1 \nFROM "base.objecttype"' {'param_1': '*'}

app.config['SQLALCHEMY_DATABASE_URI'] = "postgresql://postgres:пароль@%s/master" % session['db']