I'm not really sure, but you probably need to be calling super() somewhere
in Client.__init__, which you don't seem to be doing.
The main difference between your code and what I would usually do is that I
almost never override __init__ in my models. I expect some of the setup
for inheritance happens in DeclarativeBase (Base in your example) and that
isn't getting called, so never happens.
Try removing your __init__ methods as an easy troubleshooting step, and if
that works you know your problem is there.
On Fri, Jan 10, 2014 at 6:08 AM, <david.ceresu...@gmail.com> wrote:
> Hello all,
>
> I'm trying to use SQLAlchemy inheritance in a (company's) project and I
> cannot seem to make it work.
>
> First, the versions:
> - Ubuntu: 12.10
> - Python: 2.7.3
> - SQLAlchemy: 0.9.1
> - PostgreSQL: 9.1
> - sqlite: 3.7.13
> - Pyramid: 1.4.2
> All of the problems happen in both PostgreSQL and sqlite.
>
> I have a ClientVip class that inherits from Client. This is the trimmed
> code:
>
> ##
> class Client(Base):
> __tablename__ = 'client'
> id = Column(Integer, primary_key=True)
> ctype = Column(String(16), nullable=False)
> webaddid = Column(Integer, ForeignKey('web.id'), nullable=False)
> parentid = Column(Integer, ForeignKey('client.id'), nullable=True)
> refinternal = Column(Integer, unique=True, nullable=False)
> ...
> notestx = Column(String(256), nullable=True)
> notesclient = Column(String(256), nullable=True)
>
> __mapper_args__ = {
> 'polymorphic_identity':'basic',
> 'polymorphic_on': ctype
> }
>
> def __init__(self, webaddid=None, parentid=None, refinternal=None,
> ...
> notestx=None, notesclient=None):
> # self.ctype = "basic" ### This is actually commented, but might
> be important
> self.webaddid = webaddid
> self.parentid = parentid
> self.refinternal = refinternal
> ...
> self.notesclient = notesclient
>
>
> class ClientVip(Client):
> __tablename__ = 'clientvip'
> id = Column(Integer, ForeignKey('client.id'), primary_key=True)
> legalname = Column(String(128), nullable=True)
> commercialname = Column(String(64), nullable=True)
> ...
> isclienttop = Column(Boolean, nullable=False)
> numlisttop = Column(Integer, nullable=True)
>
> # Fill the column 'ctype' with the value 'vip'
> __mapper_args__ = {
> 'polymorphic_identity':'vip',
> }
>
> def __init__(self, clientid=None, legalname=None, commercialname=None,
> ...
> isclienttop=False, numlisttop=None, **kwargs):
>
> # First initialize the basic client
> super(ClientVip, self).__init__(**kwargs)
>
> # And then the VIP client
> # self.ctype = "vip" ### This is actually commented, but might
> be important
> self.clientid = clientid
> self.legalname = legalname
> self.commercialname = commercialname
> ...
> self.isclienttop = isclienttop
> self.numlisttop = numlisttop
> ##
>
> I have checked the code in
> -
> http://docs.sqlalchemy.org/en/rel_0_9/orm/examples.html?highlight=inheritance#module-examples.inheritance
> -
> http://docs.sqlalchemy.org/en/rel_0_9/_modules/examples/inheritance/joined.html
> and I can't find anything different, but maybe are my eyes.
>
>
> Problem: Querying client and clientvip
> -------------------------------------------------------
>
> With this code I try to query all the clients [ clients =
> DBSession.query(Client) ]
> and this is where the problems start, because the query it is issuing is:
>
> ##
> SELECT client.id AS client_id, client.ctype AS client_ctype,
> client.refinternal AS client_refinternal,
> ...
> client.notestx AS client_notestx, client.notesclient AS client_notesclient
> FROM client
> WHERE client.ctype IN (NULL)
> ##
>
> Why is there a where clause at all? Should not the query finish with the
> "FROM client" line?
> And besides, why does it think that ctype must be NULL (instead of "basic"
> or "vip", for instance)?
>
>
> If a force to query with a filter [ clients =
> DBSession.query(Client).filter(Client.ctype == "basic") ]
> this is the query I get:
>
> ##
> SELECT client.id AS client_id, client.ctype AS client_ctype,
> client.refinternal AS client_refinternal,
> ...
> client.notestx AS client_notestx, client.notesclient AS client_notesclient
> FROM client
> WHERE client.ctype = %(ctype_1)s AND client.ctype IN (NULL)
> ##
>
> which also looks for NULL values in the where clause.
>
>
> And what happens if I query the ClientVip?
> Well, there are no where clauses, so we are good:
>
> ##
> SELECT clientvip.id AS clientvip_id, client.id AS client_id, client.ctype
> AS client_ctype, client.refinternal AS client_refinternal,
> ...
> clientvip.isclienttop AS clientvip_isclienttop, clientvip.numlisttop AS
> clientvip_numlisttop
> FROM client JOIN clientvip ON client.id = clientvip.id
> ##
>
>
> Appendix: Inserting client
> -------------------------------------
>
> You might have seen that in the __init__ methods I have commented out the
> " self.ctype = 'basic' "
> When this line is commented out (as it should) and I try to insert a
> Client, I get the following error:
>
> ##
> IntegrityError: (IntegrityError) null value in column "ctype" violates
> not-null constraint
> ##
>
> which leads me to think that the polymorphism I am trying to get is not
> working properly, becasue
> I shouldn't need to force a value on the "ctype" column.
>
>
> A plea for help
> ---------------------
>
> I have been looking at this code for quite some time and I can't figure
> out what I am missing.
> If any of you have any idea of what I could be possibly doing wrong, or
> any ideas that I could
> try, I will be very very happy to hear them, because I have run out of
> ideas to try right now.
>
> Thank you very much.
>
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