Bulk query updates, you mean, query.update() ? Or session.bulk_update_mappings() ? In both cases you are programatically providing the VALUES clause, so you know from your own data what the UPDATE statement will be.
On Wed, May 15, 2019 at 4:14 PM Tony Cao <t...@benchling.com> wrote: > > Ah but it also looks like the before_update event isn't triggered when doing > bulk query updates, which we'd like to also update on. Is there a way to > track those? > > On Wednesday, May 15, 2019 at 10:38:24 AM UTC-7, Mike Bayer wrote: >> >> you can inspect() the object and look at >> inspect(obj).attrs['some_attr'].history >> >> https://docs.sqlalchemy.org/en/13/orm/internals.html#sqlalchemy.orm.state.AttributeState >> >> >> On Wed, May 15, 2019 at 1:14 PM Tony Cao <to...@benchling.com> wrote: >> > >> > Hi, >> > >> > Thanks for the response! I also tried looking into before_update, but is >> > there a recommended way to figure out what columns are being updated from >> > that event? I had found this post >> > (https://stackoverflow.com/questions/15642286/how-can-i-get-a-sqlalchemy-orm-objects-previous-state-after-a-db-update) >> > that suggests looking at the history of the attribute state - is there a >> > better way? >> > >> > On Wednesday, May 15, 2019 at 7:55:44 AM UTC-7, Mike Bayer wrote: >> >> >> >> On Mon, May 13, 2019 at 4:18 PM Tony Cao <to...@benchling.com> wrote: >> >> > >> >> > Hi all, >> >> > >> >> > Is there way to use Column.onupdate conditionally? For example, say I >> >> > have: >> >> > >> >> > class A(Base): >> >> > foo = Column(String) >> >> > bar = Column(String) >> >> > foo_updated = Column(DateTime, onupdate=update_fn) # Should only >> >> > update when foo is updated >> >> > >> >> > def update_fn(context): >> >> > if ...: # How can I check if only foo was updated? >> >> > return datetime.now() >> >> > else: >> >> > return ... # How can I say to not update? >> >> > >> >> > Is there a way to define update_fn to only update foo_updated when foo >> >> > changes? I can look at context.get_current_parameters() to see what >> >> > columns are being used in the compiled statement, but it doesn't >> >> > explicitly say which columns are the ones actually being updated; for >> >> > example, if I have >> >> > >> >> > A.query.filter(A.bar == 'test').update({A.foo: 'new'}, >> >> > synchronize_session=False) >> >> > >> >> > then context.get_current_parameters will return a dict with keys for >> >> > both 'bar' and 'foo', although it looks like it suffixes the filter >> >> > param with a '_1' - is that something I can rely on to know if a column >> >> > is used as a filter instead of an update? And beyond that, is there a >> >> > way I can specify to not update the column? >> >> > >> >> > Alternatively, is there another approach recommended to doing this? >> >> >> >> the most common way is to use the ORM level before_update event: >> >> >> >> https://docs.sqlalchemy.org/en/13/orm/events.html?highlight=before_update#sqlalchemy.orm.events.MapperEvents.before_update >> >> >> >> there's also before_execute() at the Core level, but before the UPDATE >> >> statement is even written, e.g. at the ORM level, is the best way. >> >> Once you are in the onupdate Python function, you have to return a >> >> value, as this occurs well after the UPDATE statement has been >> >> compiled. >> >> >> >> >> >> >> >> >> >> > >> >> > Thanks! >> >> > >> >> > -- >> >> > 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 sqlal...@googlegroups.com. >> >> > To post to this group, send email to sqlal...@googlegroups.com. >> >> > Visit this group at https://groups.google.com/group/sqlalchemy. >> >> > To view this discussion on the web visit >> >> > https://groups.google.com/d/msgid/sqlalchemy/b66e89c9-6618-4600-9381-182fa101f5b6%40googlegroups.com. >> >> > 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. >> > --- >> > 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 sqlal...@googlegroups.com. >> > To post to this group, send email to sqlal...@googlegroups.com. >> > Visit this group at https://groups.google.com/group/sqlalchemy. >> > To view this discussion on the web visit >> > https://groups.google.com/d/msgid/sqlalchemy/f13c4205-1df5-49c5-8c91-3c97cd8d9b05%40googlegroups.com. >> > 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. > --- > 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. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/38b1162d-1204-41b7-9649-3938775eeef8%40googlegroups.com. > 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. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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