On Tue, 2012-05-15 at 19:51 -0400, Adam Tauno Williams wrote: > On Tue, 2012-05-15 at 16:27 -0400, Michael Bayer wrote: > > Could be tough, you'd need to test it against the informix dbapi directly, > using bound parameters, to see what it needs. Could be a typing issue. > Ok, I got a response from an Informix guru and maintainer of the > informix dbapi. > <quote> > I see two different approaches around this issue: > * Use literal values instead of bound parameters in the projection > clause. > * If you must use bound parameters, use type casts for the parameters > that are used in the projection clause. For example: CASE WHEN > (xrefr.xr_supersede = :1) THEN :2::int ELSE :3::int > </quote> > I assume this same kind of issue must be addressed in other dialects???
I've constructed a sequence that seems to work perfectly.
class XrefrRecord(Base):
__tablename__ = 'xrefr'
record_id = Column("xr_serial_no", Integer, primary_key=True)
sku = Column("xr_stock_no", Integer, nullable=False)
....
list_price = Column("xr_list_price", Float(precision=3))
_supersede = Column("xr_supersede", String(1))
is_supersede = column_property(
case( [ ( _supersede == 'S',
literal_column('1', Integer) ) ],
else_ = literal_column('0', Integer)
)
)
__mapper_args__ = { 'polymorphic_on': is_supersede }
class Cross(XrefrRecord):
__mapper_args__ = {'polymorphic_identity': 0}
class Supersede(XrefrRecord):
__mapper_args__ = {'polymorphic_identity':
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