The hybrid property and custom comparator approach works like a charm, I had an inkling that hybrid propertyies were the correct approach but hadn't really thought about subclassing hybrid_property, this has helped me understand the custom types architecture a lot, thank very much.
Alex On Mon, Mar 31, 2014 at 4:13 PM, Jonathan Vanasco <jonat...@findmeon.com>wrote: > I'm interested in what you find. I know TypeDecorator is the right > solution, I was looking at that for this exact same situation a few weeks > ago ( > https://groups.google.com/forum/#!searchin/sqlalchemy/vanasco%7Csort:date/sqlalchemy/sQtOYxSUiqI/5ns2vWMFaGAJ) > > I have a similar situation. I wrote a generic bitwise wrapper class that > I was ashamed of, but I guess I should eventually release it. i can toss > it on github under the MIT if you'd like. > > The way I have my bitwise stuff working is this: > > * I create an class that inherits from my `BitwiseSet` class. That > subclass stores a mapping of the bitwise values, the parent class has > functions for common bitwise operations ( add, remove, has_any, has_all -- > both by string and integer ). The parent class has an 'encode' and > 'decode' function, which returns an int or list of elements (as int or > string ). > > class BitwiseClassFieldA(BitwiseSet): > set_ = { > 'flag_a' << 1, > 'flag_b' << 2, > 'flag_c' << 3, > } > > * I have a property on each of my sqlalchemy objects that works something > like this... > > class Foo(SqlAlchemyObject): > bitwise_field_a = sa.Column( sa.Integer, default=0 ) > > @property > def bitwise_manager_field_a(self): > if self._bitwise_manager_field_a is None: > self. bitwise_manager_field_a = > BitwiseClassFieldA(self.bitwise_field_a) > return self.bitwise_manager_field_a > _ bitwise_manager_field_a = None > > * when i do saves , i call the manager's `encode` function > > instance.bitwise_field_a = instance.bitwise_manager_field_a.encode() > > > anyways, when I was trying to get a TypeDecorator working, I was focused > on the Integer field having a decorator and managing my object -- not on > defining many column attributes like you are. i think that might be an > easier avenue, because you want to affect the column itself for these > comparisons. > > -- > 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/Mu9m1dVU1Gw/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > -- 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 http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
