Thanks, so far my new project works well in 2.0. My question is that I'm trying to migrate to the 2.0 style form using this cheetsheet:
https://docs.sqlalchemy.org/en/20/changelog/migration_20.html#migration-orm-usage So far I couldn't figure out how to turn this query in to 2.0 style. session.query(cls).filter(func.lower(cls.username) == username_lower).first() Without func.lower this is what I could came up with, however I couldn't figure out how to plug func.lower() into this one: stmt = select(cls).filter_by(username=username_lower) session.execute(stmt).scalar_one() Do I need to use .where() for this query? Also, what is the difference between .where() and .filter_by()? Just syntax and saving a bit of typing or there are more differences which could affect the performance as well? Also, for a column with a unique constraint, what should I use scalar_one() or first()? Or in this case the difference is all about returning None vs raising an Exception? Zsolt On 25. Nov 2022 at 16:56:52, Mike Bayer <mike...@zzzcomputing.com> wrote: > > > On Thu, Nov 24, 2022, at 3:24 PM, zsol...@gmail.com wrote: > > Hi, > > I'm trying to run low-level commands like DROP DATABASE / CREATE DATABASE, > with psycopg2. > > In 1.3 I used the following: > > with > pg_engine.connect().execution_options(isolation_level="AUTOCOMMIT",autocommit=True) > as conn: > conn.execute(command) > > Now in 2.0 I run into many errors. I've read the migration guide and for > me this looks like the best: > > with pg_engine.connect().execution_options(isolation_level="AUTOCOMMIT") > as conn: > conn.exec_driver_sql(command) > > > correct > > > Is this the right one? I'm confused as isolation_level is not written in > the migration guide, I just had it from 1.3. > > > the "isolation_level" parameter wasnt changed in 2.0. The "autocommit" > execution option was removed, though: > https://docs.sqlalchemy.org/en/20/changelog/migration_20.html#library-level-but-not-driver-level-autocommit-removed-from-both-core-and-orm > > > But without isolation_level it doesn't work. > > Also, what is the difference between exec_driver_sql and execute + text()? > > > the text() construct uses a dialect-agnostic bound parameter and escaping > format, and only uses named parameters. It also has other features that > allow for text() constructs to be embedded within larger select() > constructs. exec_driver_sql is a direct-to-cursor method that allows for > both named and positional parameters as handled by the DBAPI. > > overall there's no need to have lots of errors if you migrate first to 1.4 > and then use the 1.4/2.0 migration process at > https://docs.sqlalchemy.org/en/20/changelog/migration_20.html#. the > warnings will tell you most of what you need to change. > > > > Zsolt > > > > > > > -- > 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+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/d0f06e70-f341-475e-8176-8bf0ac46ff94n%40googlegroups.com > <https://groups.google.com/d/msgid/sqlalchemy/d0f06e70-f341-475e-8176-8bf0ac46ff94n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- > 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 a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sqlalchemy/R7GuWsXz1_c/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/b4e568ca-9b40-4438-9a60-b7cad1e42c7f%40app.fastmail.com > <https://groups.google.com/d/msgid/sqlalchemy/b4e568ca-9b40-4438-9a60-b7cad1e42c7f%40app.fastmail.com?utm_medium=email&utm_source=footer> > . > -- 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+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/CAKw-smDTY5dZkcMNHy7BitnV7%3D1KFXCoSOXwpH6A2avP3g3w4Q%40mail.gmail.com.
