Thks for the insight Michael. With the @property solution, its not possible to make queries like session.query(Person).filter(Person.address.street="Something") right? Cascade Saving/Updating in that instance should be a problem too. I tested the composite solution, it's nice but the queries get a bit complex to do when we want to restrict fields of the composite Object (because the need of comparator and when we want only one field of the composite object in the restriction not all of them). Not very straight forward.
What do you say about it? I really think that in real-world situations i would never want to make table become two objects, it's much more easy(implementation and understanding) to use just one object. I'm doing a paper about ORM solutions and that's why i'm asking about this specific feature. I'll give a look in the "inverse" solution later. Thanks again! 2011/4/5 Michael Bayer <mike...@zzzcomputing.com> > > On Apr 5, 2011, at 9:06 AM, Israel Ben Guilherme Fonseca wrote: > > > Hi, > > > > Is it possible to break a table in two Python objects? Ex: > > > > Python objects: > > > > class Person: > > > > name = Column(String) > > > > class Address: > > > > street = Column(String) > > city = Column(String) > > > > > > Table: > > > > table Person > > name varchar > > city varchar > > street varchar > > > > How can i make the "connection" between the two? > > You could map Person and Address both to the table, excluding/including > columns from each using mapper "include_properties/exclude_properties" (see > the docs), however relationship() would not be able to handle the join > condition of this table, which is table.id==table.id. > > So in the practical sense, you'd just do this: > > class Person(object): > @property > def address(self): > return Address(self.street, self.city) > > or similarly use a composite (search the mapping documentation for > "composite") to achieve the Address class composed of that subset of > columns. If you choose "composite" I'd note 0.7 improves upon the > scalability of the "composite" feature significantly (for small datasets in > memory it doesn't matter though). > > > And is it possible to make the inverse? (table Person and Address to a > single Python object Person) > > you can map to a join of the two tables as described at > http://www.sqlalchemy.org/docs/orm/mapper_config.html#mapping-a-class-against-multiple-tables > . > > -- > 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.
