[sqlalchemy] Re: session.query().get() is unsupported during flush for getting an object that was just added?
On Feb 1, 3:17 pm, Kent jkentbo...@gmail.com wrote: If the value is based on what's already been INSERTed for previous rows, I'd emit a SQL statement to get at the value.If it's based on some kind of natural consideration that isn't dependent on the outcome of an INSERT statement, then you can do the looping above within the before_flush() event and assign everything at once.Basically you need to batch the same way the UOW itself does. is IdentitySet an OrderedSet? if I loop through session.new, for example, am I guaranteed to hit these in the same order they were added to the session? Is there a way to work out the order in which session.new items were added... I take it session.new is not ordered. Did you mention you were in the works of an instance level event for 'before_flush()', similar to 'before_insert/before_update'? -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Re: session.query().get() is unsupported during flush for getting an object that was just added?
On Feb 6, 2012, at 4:05 PM, Kent wrote: On Feb 1, 3:17 pm, Kent jkentbo...@gmail.com wrote: If the value is based on what's already been INSERTed for previous rows, I'd emit a SQL statement to get at the value.If it's based on some kind of natural consideration that isn't dependent on the outcome of an INSERT statement, then you can do the looping above within the before_flush() event and assign everything at once.Basically you need to batch the same way the UOW itself does. is IdentitySet an OrderedSet? if I loop through session.new, for example, am I guaranteed to hit these in the same order they were added to the session? Is there a way to work out the order in which session.new items were added... I take it session.new is not ordered. InstanceState has an attribute insert_order that's assigned as objects are added, so the sort at flush time is based on that attribute. It is unique across all of session.new. Did you mention you were in the works of an instance level event for 'before_flush()', similar to 'before_insert/before_update'? there's room to support a series of extensions to the before_flush() listener such that it would provide filtered collections or individual instances to the listener callable.Some notion of this was always in mind, though actually implementing it is way down on my list of priorities.It would be implemented within a _listen method on SessionEvents. _listen() is called by the event system when a user-defined listener function is first established against an event.In this case the given listener function would be wrapped inside a filtering callable that calls it as many times as needed passing in the appropriate objects.For examples of listeners being wrapped on listen, see AttributeEvents._listen, InstanceEvents._listen, MapperEvents._listen. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] Re: session.query().get() is unsupported during flush for getting an object that was just added?
If the value is based on what's already been INSERTed for previous rows, I'd emit a SQL statement to get at the value.If it's based on some kind of natural consideration that isn't dependent on the outcome of an INSERT statement, then you can do the looping above within the before_flush() event and assign everything at once.Basically you need to batch the same way the UOW itself does. is IdentitySet an OrderedSet? if I loop through session.new, for example, am I guaranteed to hit these in the same order they were added to the session? -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
