I believe zope.sqlalchemy has no group/mailing list, so this message
is specifically intended for zope.sqlalchemy developers (whom I'll
point to this thread):
Please read the above.
Here is a script to demonstrate the behavior zope.sqlalchemy is
causing. I believe is not an intended behavior (i.e. I think this is a
bug):
===================================
from sqlalchemy import *
from sqlalchemy.orm import scoped_session, sessionmaker
from zope.sqlalchemy import ZopeTransactionExtension
from zope.sqlalchemy import __version__ as zopesqlaversion
import transaction
print "zope.sqlalchemy version %s" % zopesqlaversion
engine = create_engine('sqlite:///', echo=True)
session_maker = sessionmaker(bind=engine,
extension=ZopeTransactionExtension())
Session = scoped_session(session_maker)
Session.execute("create table kb (data varchar)")
Session.execute("insert into kb values ('data')")
fetched = Session.execute("select * from kb").fetchall()
print "fetched: %r" % fetched
assert fetched == [('data',)]
# if we use sqla alone, Session.commit() would issue a commit
# zope.sqlalchemy thinks there is nothing to commit, unless there are
changes to
# actual sqla *objects* (then this would issue COMMIT)
transaction.commit()
Session = scoped_session(session_maker)
# now we see there was no data committed
fetched = Session.execute("select * from kb").fetchall()
print "fetched: %r" % fetched
assert fetched == [('data',)]
===================================
Here is the scripts output:
===================================
zope.sqlalchemy version 0.6
2010-12-17 10:35:45,684 INFO sqlalchemy.engine.base.Engine.0x...b0d0
BEGIN
2010-12-17 10:35:45,689 INFO sqlalchemy.engine.base.Engine.0x...b0d0
create table kb (data varchar)
2010-12-17 10:35:45,690 INFO sqlalchemy.engine.base.Engine.0x...b0d0
()
2010-12-17 10:35:45,693 INFO sqlalchemy.engine.base.Engine.0x...b0d0
insert into kb values ('data')
2010-12-17 10:35:45,694 INFO sqlalchemy.engine.base.Engine.0x...b0d0
()
2010-12-17 10:35:45,695 INFO sqlalchemy.engine.base.Engine.0x...b0d0
select * from kb
2010-12-17 10:35:45,696 INFO sqlalchemy.engine.base.Engine.0x...b0d0
()
fetched: [(u'data',)]
2010-12-17 10:35:45,698 INFO sqlalchemy.engine.base.Engine.0x...b0d0
BEGIN
2010-12-17 10:35:45,700 INFO sqlalchemy.engine.base.Engine.0x...b0d0
select * from kb
2010-12-17 10:35:45,701 INFO sqlalchemy.engine.base.Engine.0x...b0d0
()
fetched: []
Traceback (most recent call last):
File "zopedemo.py", line 28, in <module>
assert fetched == [('data',)]
AssertionError
===================================
Thank you for your time/response.
Kent
On Dec 17, 9:40 am, Kent <jkentbo...@gmail.com> wrote:
> I had mistaken it for a SQLA flaw, but, from pdb, it appears the
> behavior I'm observing is being caused by zope.sqlalchemy.
>
> Thanks for your input.
>
> On Dec 16, 7:19 pm, Michael Bayer <mike...@zzzcomputing.com> wrote:
>
> > That doesn't sound right. Session.commit() issues the commit regardless
> > of whether or not flush() had any work to do. The usage of
> > Session.execute() takes place in the scope of the Session's transaction so
> > work is definitely begun as well.
>
> > from sqlalchemy import create_engine
> > from sqlalchemy.orm import Session
>
> > e = create_engine('sqlite:///test.db', echo=True)
> > s = Session(e)
>
> > s.execute("CREATE TABLE foo (data VARCHAR)")
> > s.execute("INSERT INTO foo (data) VALUES ('data1')")
> > s.commit()
> > s.close()
>
> > e = create_engine('sqlite:///test.db', echo=True)
>
> > assert e.execute("SELECT * FROM foo").fetchall() == [('data1',)]
>
> > On Dec 16, 2010, at 2:37 PM, Kent wrote:
>
> > > From time to time I find I need or prefer "dropping into SQL" for
> > > certain tasks, in the midst of making the majority of my database
> > > changes through sqlalchemy's objects; for example, I may use
> > > session.execute(sql).
>
> > > I would like these changes to be committed later along with the sqla
> > > session objects *if and only if* the session issues a commit.
> > > However, I've observed that if the *only* database changes were made
> > > via session.execute(), then session.commit() believes there is nothing
> > > to commit, so the "commit" isn't issued to the database.
>
> > > Is there a better way to approach what I am trying to accomplish?
> > > Is there a way to tell a session "by the way, you have changes that
> > > you don't know about, so when it comes time to commit, please do so"?
>
> > > Thanks very much, as always,
> > > Kent
>
> > > --
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>
>
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