Using objects outside of the session`s scope in sqlalchemy


I have an Job object that I create in the beginning of some API call:

class Job(Base):
    __tablename__ = 'jobs'
    id = Column(BIGINT, primary_key=True)
    end_date = Column('end_date', DateTime(timezone=True), nullable=False)
    start_date = Column('start_date', DateTime(timezone=True), default=datetime.datetime.utcnow(), nullable=False)
    name = Column('name', TEXT, nullable=False)

    def __init__(self, name): = name
        self.start_date = datetime.datetime.utcnow()
        self.end_date = 'infinity'

When the api is called I’m creating a new job :


However, after the job starts I want to send this job object as a parameter to some other flows in order to know which job was responsible for that flow.

The problem is that after I closed the session I can’t use the Python object job, I will get the following error :

sqlalchemy.orm.exc.DetachedInstanceError: Instance <Job at 0x3c67f30> is not bound to a Session; attribute refresh operation cannot proceed (Background on this error at:

I want to save the job object before it starts. Anyway, can I use it outside of the session’s scope, but after I saved it? I know that I can query it afterwards, but I don’t want to, I want to work with the same job object I created.

My current solution :

get_job_id_query = (
.find( == 'infinity')
.filter( ==
job_id = get_job_id_query.all()[0][0]

and then I pass the id to the next flows.

Asked By: JeyJ



Session takes an expire_on_commit argument that will leave objects accessible after being committed if it is set to False.

When using it, you need to be aware that “expired” objects will be out of sync with the database if the data is updated by anothe session.

Answered By: snakecharmerb
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