On Aug 3, 2011, at 9:58 AM, Damian Dimmich wrote: > Hi All, > > I've been experimenting with the new event system in 7.1, and I'd like > to use it to set some values in my tables on each insert/update. > Basically, I've created a mixin class (BaseMixin) which adds two fields > to each model that inherits the mixin - a user_id and a last updated > field which I want to use for audit purposes. A separate > history/versioning system will come after this. > > The function attach_user_committing gets called on a flush, and in it I > can find all the newly added objects to the session by inspecting > Session._new, but I'm not sure how to determine which ones have been > updated. Any suggestions/comments on the below would be greatly > appreciated!
session.dirty will have the list of all objects marked potentially "dirty", the session.is_modified() method can return a boolean for an individual object that checks more fully if there are net changes on the object, and attributes.get_history(attr) will give you the information on an individual attribute. Examples of this are in the various versioning demos we have. http://www.sqlalchemy.org/docs/orm/session.html?highlight=dirty#sqlalchemy.orm.session.Session.dirty http://www.sqlalchemy.org/docs/orm/session.html?highlight=is_modified#sqlalchemy.orm.session.Session.is_modified http://www.sqlalchemy.org/docs/orm/session.html?highlight=get_history#sqlalchemy.orm.attributes.get_history http://www.sqlalchemy.org/docs/orm/examples.html#versioned-objects http://www.sqlalchemy.org/trac/wiki/UsageRecipes/VersionedRows http://www.sqlalchemy.org/trac/wiki/UsageRecipes/VersionedMap > > Thanks, > Damian > > def attach_user_committing(Session, flush_context, instances): > user_id = > authenticated_userid(pyramid.threadlocal.get_current_request()) > #for each object being committed/flushed, set the flushing/commiting > user > for obj in Session._new.values(): > obj.user_id = user_id > obj.last_updated = datetime.now() > > #this event ensures that user_id & lastupdate is correctly updated on > each flush. > event.listen(Session, "before_flush", attach_user_committing) > > #We add lastupdate and userid fields (and mappings) > #to the base class for inheritance > class BaseMixin(object): > @sa.ext.declarative.declared_attr > def user_id(cls): > return sa.Column(sa.Integer, sa.ForeignKey('users.id'), > nullable=False) > @sa.ext.declarative.declared_attr > def last_update_date(cls): > return sa.Column(sa.DateTime, > default=datetime.now()) > @sa.ext.declarative.declared_attr > def user(cls): > return orm.relationship('User') > > -- > 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. > -- 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.
