Hello, Mike!
In my web app i have many selects like
session.execute(select([table1]).where(condition))
and not so much updates, inserts and deletes like
session.execute(update(table1).where(condition).values(**values))
session.execute(insert(table1).values(**values))
session.execute(delete(table1).where(condition))
What better way to create session for web application?
Without additional components like flask-sqlalchemy.
суббота, 27 января 2018 г., 20:23:05 UTC+3 пользователь Mike Bayer написал:
>
> On Sat, Jan 27, 2018 at 5:49 AM, Евгений Рымарев
> <rymarev...@gmail.com <javascript:>> wrote:
> > I receive this error:
> > This result object does not return rows. It has been closed
> automatically.
>
> there's a lot of weird situations which can cause that error, usually
> when using a connection that has had some failure condition occur upon
> it which renders the connection unusable until either a transaction is
> rolled back or sometimes the connection needs to be discarded. We
> can't diagnose it without a full example that reproduces it as well as
> the complete stack trace.
>
>
> >
> >
> >
> > суббота, 27 января 2018 г., 1:09:53 UTC+3 пользователь Mike Bayer
> написал:
> >>
> >> On Fri, Jan 26, 2018 at 4:21 PM, Евгений Рымарев
> >> <rymarev...@gmail.com> wrote:
> >> > Hello, everyone!
> >> > Engine:
> >> > engine = create_engine(
> >> >
> >> >
> >> >
> 'mssql+pymssql://{LOGIN}:{PASSWORD}@{HOST}/{DATABASE}?charset={CHARSET}'.format(**DATABASE),
>
>
> >> > isolation_level='READ COMMITTED'
> >> > )
> >> >
> >> >
> >> > My first decorator for session:
> >> > @decorator_with_args
> >> > def session_decorator(func, default=None):
> >> > def wrapper(*a, **kw):
> >> > s = Session(engine)
> >> > kw['session'] = s
> >> > try:
> >> > return func(*a, **kw)
> >> > except Exception as e:
> >> > func(*a, **kw)
> >> > s.rollback()
> >> > s.close()
> >> > logging.error(e)
> >> > return default
> >> > finally:
> >> > s.commit()
> >> > s.close()
> >> > return wrapper
> >> >
> >> > My second decorator for session:
> >> > session = scoped_session(sessionmaker(bind=engine))
> >> >
> >> >
> >> > @decorator_with_args
> >> > def session_decorator(func, default=None):
> >> > def wrapper(*a, **kw):
> >> > kw['session'] = session
> >> > try:
> >> > return func(*a, **kw)
> >> > except Exception as e:
> >> > session.remove()
> >> > logging.error(e)
> >> > return default
> >> > finally:
> >> > session.remove()
> >> > return wrapper
> >> >
> >> > In both attempts, I came to the conclusion that sessions can block
> other
> >> > sessions.
> >> > How correctly to create a session once, so that it can be used
> >> > throughout
> >> > the web application and no locks were created?
> >>
> >> The Session doesn't create locks, transactions and your database does.
> >>
> >> What is the nature of these "blocks", are they deadlocks between
> >> tables or rows? What operations are prevented from proceeding? Are
> >> the locks timing out? SQL Server has graphical consoles that can
> >> show you this.
> >>
> >> What version of SQL Server is this? Do you have
> >> ALLOW_SNAPSHOT_ISOLATION and READ_COMMITTED_SNAPSHOT turned on?
> >>
> >>
> >> >
> >> > --
> >> > SQLAlchemy -
> >> > The Python SQL Toolkit and Object Relational Mapper
> >> >
> >> > http://www.sqlalchemy.org/
> >> >
> >> > To post example code, please provide an MCVE: Minimal, Complete, and
> >> > Verifiable Example. See http://stackoverflow.com/help/mcve for a
> full
> >> > description.
> >> > ---
> >> > You received this message because you are subscribed to the Google
> >> > Groups
> >> > "sqlalchemy" group.
> >> > To unsubscribe from this group and stop receiving emails from it,
> send
> >> > an
> >> > email to sqlalchemy+...@googlegroups.com.
> >> > To post to this group, send email to sqlal...@googlegroups.com.
> >> > Visit this group at https://groups.google.com/group/sqlalchemy.
> >> > For more options, visit https://groups.google.com/d/optout.
> >
> > --
> > SQLAlchemy -
> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
> > To post example code, please provide an MCVE: Minimal, Complete, and
> > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > description.
> > ---
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> <javascript:>.
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>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
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