Issue with relationship

[Emanuel Vitorino]

Hi all

I've updated an old sql alchemy powered application and I'm struggling with a relationship issue.

Having this code:

class Member(object):
  _data_provider = inject.attr(DataProvider)

  def __init__(self, id_member=None, name=None):

    self.id_member = id_member

    self.name = name

     self.alocs = []

  def save(self):

     auto_projects = self._data_provider.list_projects_aloc_auto()

     self.alocs = [Aloca(project_id=project.id, member.id=self.id, date=datetime.datetime.now()) for project in auto_projects]

     self._data_provider.save_member(self)

class Project(object):

  _data_provider = inject.attr(DataProvider)

  def __init__(self, id, name):

     self.id = id

     self.name = name

     self.places = []

class Aloc(object):

  _data_provider = inject.attr(DataProvider)

  def __init__(self, id, id_project, date):

     self.id = id

     self.id_project = id_project

     self.date = date

class AutoAloc(Aloc):

  pass

class Manager(Aloc):

  pass

from sqlalchemy.schema import MetaData, Table, Column, ForeignKey

class DataProvider(object):

  _metadata = MetaData()
  _engine = None
  _SessionFactory = sessionmaker(expire_on_commit=False) # Factory de sessões

  

  def _map_aloc(self):

    alocs = Table("aloc", self._metadata,
      Column("id", Integer, primary_key=True),
      Column("id_project", Integer, ForeignKey("project.id")),
      Column("date", DateTime),
      mysql_engine='InnoDB',
      mysql_charset='utf8')
      return mapper(Aloc, alocs,
          polymorphic_on=alocs.c.type,
          polymorphic_identity="aloc",
      )

  def _map_manager(self, aloc_mapper):

     return mapper(Manager, inherits=aloc_mapper, polymorphic_identity='manager')

  def _map_aloc_auto(self, aloc_mapper):
     return mapper(AlocAuto, inherits=alocacao_mapper, polymorphic_identity='alocauto')

   def _map_project(self):

      projects = Table("project", self._metadata,
         Column("id", Integer, primary_key=True),
         Column("name", String(255)),

         mysql_engine='InnoDB',

         mysql_charset='utf8')

     

         return mapper(Project, projects,

              "managers": relationship(Manager),
               "alocs": relationship(Aloc, backref="project", cascade="all, delete-orphan")})

  

  def _map_member(self):
     members = Table("member", self._metadata,
     Column("id", Integer, primary_key=True),
     Column("name", String(255)),

     mysql_engine='InnoDB',
     mysql_charset='utf8')

 

     return mapper(Member, members,

                                 polymorphic_on=members.c.type,
                                 polymorphic_identity="member",
                                 alocs": relationship(Aloc, backref="member", cascade="all,delete- orphan"),
                               })

  def __init__(self, connection_string, connection_pool_size, disable_overflow=True):

      if DataProvider._engine is None:
         if disable_overflow:
            DataProvider._engine = create_engine(connection_string, max_overflow=0, pool_size=connection_pool_size)
         else:
             DataProvider._engine = create_engine(connection_string, pool_size=connection_pool_size)
             DataProvider._SessionFactory.configure(bind=self._engine)

   self._map_project()

    self._map_member()

    aloc_mapper = self._map_aloc()

   self._map_aloc_auto(aloc_mapper)

   self._map_manager(aloc_mapper)

def save_member(self, member):

  self._session.add(member)

  return member

Of course, more fields and methods in all classes... 

The issue is, when adding a new Member, member.alocs get's filled with some objects.
It creates the record in DB but project_id is null.

I receive this debug message:

/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:3441: SAWarning: relationship 'Aloc.project' will copy column project.id to column aloc.project_id, which conflicts with relationship(s): 'Manager.manager
es' (copies project.id to aloc.project_id). If this is not the intention, consider if these relationships should be linked with back_populates, or if viewonly=True should be applied to one or more if they are read-only. For the le
ss common case that foreign key constraints are partially overlapping, the orm.foreign() annotation can be used to isolate the columns that should be written towards.   The 'overlaps' parameter may be used to remove this warning. (Backg
round on this error at: http://sqlalche.me/e/14/qzyx)
 util.warn(
/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/relationships.py:3441: SAWarning: relationship 'Project.aloc' will copy column project.id to column aloc.project_id, which conflicts with relationship(s): 'Project.managers' (copies project.id to aloc.project_id). If this is not the intention, consider if these relationships should be linked with back_populates, or if viewonly=True should be applied to one or more if they are read-only. For the l
ess common case that foreign key constraints are partially overlapping, the orm.foreign() annotation can be used to isolate the columns that should be written towards.   The 'overlaps' parameter may be used to remove this warning. (Back
ground on this error at: http://sqlalche.me/e/14/qzyx)

Please consider that I might mistaken myself in project_id. Might be id_project and typos like those.

Please. any idea?

kind regards,

Emanuel