@Michael Bayer:
I successfully ran your script and like my previous tests using variables 
to stored the results of the queries : only a single SQL query was sent.

Le mardi 21 mai 2013 17:31:10 UTC+2, Etienne Rouxel a écrit :
>
> Hello
> In my program, I was trying to guess why so many SQL queries were sent 
> while some could have been avoided with the help of the identity map.
> So, I reduced my program to what is below and wrote 3 times the same 
> query.get call and 3 SQL queries were sent to the database server.
> Why does SQLAlchemy send 3 times the SQL while it could have done it only 
> 1 time for the first call and use the identity map for the 2 last calls?
>
> from sqlalchemy import *
> from sqlalchemy.orm import *
> from sqlalchemy.ext.declarative import declarative_base
> Base = declarative_base()
>
> _descriptiontype_table = Table('descriptiontype', Base.metadata,
>         Column('id', Integer, primary_key=True),
>         Column('refno', Integer),
>         Column('sortindex', Integer),
>         Column('designation', String),
>         schema='botany'
>     )
>
> class Descriptiontype(Base):
>     __table__ = _descriptiontype_table
>
> if __name__ == '__main__':
>
>     engine = create_engine('postgresql://user@localhost:5432/mydatabase')
>     Session = sessionmaker(bind=engine)
>     session = Session()
>
>     session.query(Descriptiontype).get(-2147483648)
>     session.query(Descriptiontype).get(-2147483648)
>     session.query(Descriptiontype).get(-2147483648)
>
>
>

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