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Problem transferring data using SQLAlchemy session object in loop

I have a problem with SQLalchemy database. Here is my script. I have a list of records that need to be added to the table. Once the records are added to the table, I need to get the inserted record identifiers and make another insert into the second table. I perform this operation in one session. The structure of the code is given below, since I am not allowed to specify the code

creates a session object

encode the list of records you want to insert:

 do the session.add(obj)

 session.commit()

 get obj.id

 do the session.add(obj2) # with obj2 having the id from the obj

 session.commit()

here only the latest data is written correctly if we have several records

Can anyone help me fix this issue.

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2 answers

, :

Session = sqlalchemy.orm.sessionmaker(...)
def transaction(self, callback):
  session = sqlalchemy.orm.scoped_session(Session)
  try:
    result = callback(session)
  except:
    session.rollback()
    raise
  else:
    session.commit()
  finally:
    session.close()
  return result

, :

def updatetxn(pk, newvalue):
  def txn(session):
    obj = session.query(myclass).filter_by(id=pk).one()
    obj.field = newvalue
    session.add(obj)
  return txn

transaction(updatetxn(4, 'abc'))

/ , .

+4

, ; sqlalchemy , , , , . relationship. :

>>> from sqlalchemy import *
>>> from sqlalchemy.orm import *
>>> from sqlalchemy.ext.declarative import declarative_base
>>> Base = declarative_base()

>>> class A(Base):
...     __tablename__ = "a_table"
...     id = Column(Integer, primary_key=True)
... 
>>> class B(Base):
...     __tablename__ = "b_table"
...     id = Column(Integer, primary_key=True)
...     a_id = Column(Integer, ForeignKey(A.id))
...     a = relationship(A)
... 
>>> my_a = A()
>>> my_b = B()
>>> my_b.a = my_a
>>>

, A B B.a. , , sqlalchemy a_id.

>>> engine = create_engine("sqlite:///:memory:")
>>> Base.metadata.create_all(engine)
>>> engine.echo = True
>>> Session = sessionmaker(engine)
>>> 
>>> session = Session()
>>> session.add(my_a)
>>> session.add(my_b)
>>> 
>>> session.commit()

echo=True :

2011-09-16 17:19:22,367 INFO sqlalchemy.engine.base.Engine.0x...ed50 BEGIN (implicit)
2011-09-16 17:19:22,368 INFO sqlalchemy.engine.base.Engine.0x...ed50 INSERT INTO a_table DEFAULT VALUES
2011-09-16 17:19:22,368 INFO sqlalchemy.engine.base.Engine.0x...ed50 ()
2011-09-16 17:19:22,369 INFO sqlalchemy.engine.base.Engine.0x...ed50 INSERT INTO b_table (a_id) VALUES (?)
2011-09-16 17:19:22,369 INFO sqlalchemy.engine.base.Engine.0x...ed50 (1,)
2011-09-16 17:19:22,369 INFO sqlalchemy.engine.base.Engine.0x...ed50 COMMIT

, my_a , sqlalchemy my_b.

+7

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