Thank you Michael. This solves the problem and... shows a new one.
So this is my update CourseSet
class CourseSet(Base,AbstractContainer):
@classproperty
def __mapper_args__(self):
args = dict()
args.update(AbstractContainer.__mapper_args__)
args.update({'polymorphic_identity':
'org.sakaiproject.coursemanagement.impl.CourseSetCmImpl'})
return args
Because there is several discriminant values, I need to create other ones:
class CanonicalCourse(Base,AbstractContainer):
@classproperty
def __mapper_args__(self):
args = dict()
args.update(AbstractContainer.__mapper_args__)
args.update({'polymorphic_identity':
'org.sakaiproject.coursemanagement.impl.CanonicalCourseCmImpl'})
return args
But this last one will fail, i've the following error message:
sqlalchemy.exc.InvalidRequestError: Table 'CM_MEMBER_CONTAINER_T' is
already defined for this MetaData instance. Specify
'useexisting=True' to redefine options and columns on an existing
Table object.
I could use useexisting=True but i don't know if it's the right
solution. Any ideas ?
Cheers,
Julien.
On Mon, Sep 27, 2010 at 1:02 AM, Michael Bayer <[email protected]> wrote:
>
> On Sep 26, 2010, at 6:38 PM, Julien Iguchi-Cartigny wrote:
>
>> Hi,
>>
>> I'm trying to use polymorphic_on with several inheritances:
>>
>> engine = create_engine(
>> 'mysql://xxx:y...@localhost:3306/zzz?charset=utf8&use_unicode=0',
>> pool_recycle=3600, echo=True)
>>
>> Base = declarative_base()
>>
>> class AbstractPersistent(object):
>> version = Column('VERSION', Integer)
>> last_modified_by = Column('LAST_MODIFIED_BY', String(255))
>> last_modified_date = Column('LAST_MODIFIED_DATE', Date)
>> created_by = Column('CREATED_BY', String(255))
>> created_date = Column('CREATED_DATE', Date)
>>
>> class AbstractNamed(AbstractPersistent):
>> eid = Column('ENTERPRISE_ID', String(255))
>> title = Column('TITLE', String(255))
>> description = Column('DESCRIPTION', String(255))
>>
>> class AbstractContainer(AbstractNamed):
>> __tablename__ = 'CM_MEMBER_CONTAINER_T'
>> id = Column('MEMBER_CONTAINER_ID',Integer,primary_key=True)
>> discriminator = Column('CLASS_DISCR', String(100))
>> __mapper_args__ = {'polymorphic_on': discriminator }
>>
>> class CourseSet(Base,AbstractContainer):
>> __mapper_args__ = {'polymorphic_identity':
>> 'org.sakaiproject.coursemanagement.impl.CourseSetCmImpl'}
>
> AbstractContainer is not mapped, its a mixin, so its __mapper_args__ are not
> used until a subclass of Base is invoked, which starts up a declarative
> mapping. Your only mapped class then is CourseSet, which has its own
> __mapper_args__ , that override those of AbstractContainer - they are ignored.
>
> To combine __mapper_args__ from a mapped class with those of a mixin, see the
> example at
> http://www.sqlalchemy.org/docs/orm/extensions/declarative.html?highlight=declarative#combining-table-mapper-arguments-from-multiple-mixins
> . It uses __table_args__ but the same concept of creating a full dictionary
> of arguments applies for __mapper_args__ as well.
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "sqlalchemy" group.
> To post to this group, send email to [email protected].
> To unsubscribe from this group, send email to
> [email protected].
> For more options, visit this group at
> http://groups.google.com/group/sqlalchemy?hl=en.
>
>
--
"Trouble-a-cat limited"
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en.
