In SQLAlchemy documentation there is an example of handling session with
context manager:
from contextlib import contextmanager
@contextmanagerdef session_scope():
"""Provide a transactional scope around a series of operations."""
session = Session()
try:
yield session
session.commit()
except:
session.rollback()
raise
finally:
session.close()
What are real benefits of creating new session vs. returning the same
session kept at module level in above approach? Some objects like query
will keep session reference even after session.close(), so created session
is not guaranteed to end with contextmanager call. Then it may lead to
'sqlalchemy.exc.InvalidRequestError: is already attached to session'
exceptions. Of course in the docs there is a warning above approach is for
"advanced developers", who can sort out any issue or risk their advanced
badge revoked...
Is there any way to list all sqlalchemy session objects? It may be useful
id debugging.
Regards, Jacek
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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