Hello,
I have to association proxies in code one is working and other not. I went
through it many times and wasnt able to identify issue.
Also please can you give me advice how to debug such issues if there is any?
Thanks
Jano
code:
from sqlalchemy import Column, Integer, String, ForeignKey, DateTime, Time,
ForeignKeyConstraint, and_, create_engine
from sqlalchemy.ext.associationproxy import association_proxy
from sqlalchemy.ext.declarative import declared_attr, declarative_base
from sqlalchemy.orm import relationship, backref, sessionmaker
engine_qualys =
create_engine('mysql+pymysql://qualys:123456@localhost/sqlalchemy_test')
Base = declarative_base()
Base.metadata.create_all(engine_qualys)
Session = sessionmaker(bind=engine_qualys)
class BaseMixin():
@declared_attr
def __tablename__(cls):
return cls.__name__.lower()
def __repr__(self):
values = ', '.join("%s=%r" % (n, getattr(self, n)) for n in
self.__table__.c.keys())
return "%s(%s)" % (self.__class__.__name__, values)
class Request(BaseMixin, Base):
id = Column(Integer, primary_key=True)
ip = Column(String(30))
*#working*
* servers = association_proxy('request_servers', 'server',
creator=lambda server: Request2Server(server=server))*
class Server(BaseMixin, Base):
ip = Column(String(30), primary_key=True, autoincrement=False)
class Request2Server(BaseMixin, Base):
request_id_fk = Column(Integer, ForeignKey('request.id'),
primary_key=True)
server_ip_fk = Column(String(30), ForeignKey('server.ip'),
primary_key=True)
data = Column(String(30))
request = relationship('Request', backref=backref('request_servers'))
server = relationship('Server', backref=backref('server_requests'))
*#not working*
* patches = association_proxy('patches', 'patch', creator=lambda p:
Server2Patch(patch=p))*
class Patch(BaseMixin, Base):
qid = Column(Integer, primary_key=True)
class Server2Patch(BaseMixin, Base):
request2server_request_id_fk = Column(Integer,
ForeignKey('request2server.request_id_fk'), primary_key=True)
request2server_server_ip_fk = Column(String(30),
ForeignKey('request2server.server_ip_fk'), primary_key=True)
patch_qid_fk = Column(Integer, ForeignKey('patch.qid'),
primary_key=True)
request_server = relationship('Request2Server',
backref=backref('patches'), foreign_keys=[request2server_request_id_fk,
request2server_server_ip_fk])
patch = relationship('Patch', backref=backref('request_servers2patch'),
foreign_keys=[patch_qid_fk])
__table_args__ = (ForeignKeyConstraint([request2server_request_id_fk,
request2server_server_ip_fk],
[Request2Server.request_id_fk,
Request2Server.server_ip_fk]),
{})
Base.metadata.create_all(engine_qualys)
s = Session()
#generating some data
request1 = Request(scan_title='tttt', ip='1.1.1.1,2.2.2.2')
server1 = Server(ip='1.1.1.1')
server2 = Server(ip='2.2.2.2')
request1.servers.append(server1)
request1.servers.append(server2)
request1_server1 = request1.request_servers[0]
patch1 = Patch(qid=1)
s.add_all([request1, server1, server2, patch1])
s.commit()
*#this is not working*
*request1_server1.patches.append(patch1):*
Traceback (most recent call last):
File "<input>", line 1, in <module>
File
"/home/saki/PycharmProjects/sqlalchemy_test/venv/lib64/python3.7/site-packages/sqlalchemy/orm/collections.py",
line 1113, in append
item = __set(self, item, _sa_initiator)
File
"/home/saki/PycharmProjects/sqlalchemy_test/venv/lib64/python3.7/site-packages/sqlalchemy/orm/collections.py",
line 1078, in __set
item = executor.fire_append_event(item, _sa_initiator)
File
"/home/saki/PycharmProjects/sqlalchemy_test/venv/lib64/python3.7/site-packages/sqlalchemy/orm/collections.py",
line 715, in fire_append_event
self.owner_state, self.owner_state.dict, item, initiator
File
"/home/saki/PycharmProjects/sqlalchemy_test/venv/lib64/python3.7/site-packages/sqlalchemy/orm/attributes.py",
line 1134, in fire_append_event
value = fn(state, value, initiator or self._append_token)
File
"/home/saki/PycharmProjects/sqlalchemy_test/venv/lib64/python3.7/site-packages/sqlalchemy/orm/attributes.py",
line 1444, in emit_backref_from_collection_append_event
child_impl = child_state.manager[key].impl
KeyError: 'request_server'
--
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http://www.sqlalchemy.org/
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