On Tue, Aug 22, 2017 at 9:26 AM, Konstantin Kashin <kvkas...@gmail.com> wrote: > # Setup > Suppose I have a table with two fields: a string primary key and a boolean > flag. I want to query multiple rows and then update the flag across all of > them, then commit my changes. I have a MySQL DB with the following DBAPI > (http://mysql-python.sourceforge.net/MySQLdb-1.2.2/public/MySQLdb-module.html). > > ## Model > class TestSQLTable(Base): > __tablename__ = 'test_table' > > > some_string_id = Column(String(32), nullable=False, primary_key=True) > flag = Column(Boolean, nullable=False, default=True) > > > # SQLAlchemy 1.0.12 > > In SQLAlchemy 1.0.12, the following worked: > > > sm = sessionmaker( > autocommit=False, > autoflush=True, > expire_on_commit=True, > bind=engine, # MySQL engine > ) > session_factory = scoped_session(sm) > > > def modify_records(session, flag=False): > records = session.query(TestSQLTable).all() > for r in records: > r.flag = flag > > > session = session_factory() > modify_records(session) > session.commit() > > > > # SQLAlchemy 1.1.13 > Now, this does *not* work and causes a core dump. I am unable to tell what > change was made in 1.1 that causes this different behavior when reading the > ["What's New in SQLAlchemy > 1.1?"](http://docs.sqlalchemy.org/en/latest/changelog/migration_11.html) > guide. > > If I do this in a Jupyter notebook, for instance, the kernel just crashes on > commit without any error. > > However, this **does** work for just a single row: > > def modify_record(session, flag=False): > record = session.query(TestSQLTable).first() > record.flag = flag > > > ## Ways I have gotten this to work > > ### Add an explicit return > > def modify_records(session, flag=False): > records = session.query(TestSQLTable).all() > for r in records: > r.flag = flag > return records # ADD THIS! > > > ### Flush after each mutation > > > def modify_records(session, flag=False): > records = session.query(TestSQLTable).all() > for r in records: > r.flag = flag > session.flush() # ADD THIS! > > > ### Restructure code so that the commit happens inside `modify_records` > > This works, but is not the way the application is currently built and would > thus require a major refactor (b/c commit happens via a decorator). > > # Main question > > Why does this happen exactly for multiple records and why did this work in > 1.0 but does not in 1.1?
What platform are you running this on, and how have you installed MySQLdb and SQLAlchemy? If you ugraded SQLAlchemy in-place, is there any chance that you are running a mix of old and new code? Have you reproduced the error in a completely fresh installation? Simon -- 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 post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
