If your model is based all on one table called "parent", it can only have one column called "child_value" and it can only be of a single database type, since that's your CREATE TABLE. I'm not able to follow what your example intends to do as you seem to be creating many Column objects with the same name and different types, all against a single table. That's not possible in relational databases.
On Sat, Aug 22, 2020, at 12:18 PM, Mike Bayer wrote: > Hi, I have no idea what the problem is and would need a fully runnable MCVE. > Below is part of your test which I've tried to get running but it still > errors out on identifiers missing and such, additionally I need a working > example of exactly the session operations you are trying to achieve. It > might be easier to post the working code example as a github question: > https://github.com/sqlalchemy/sqlalchemy/issues > > code so far below: > > import enum > > import sqlalchemy as sa > from sqlalchemy.dialects.postgresql import ARRAY > from sqlalchemy.dialects.postgresql import HSTORE > from sqlalchemy.ext.mutable import MutableDict > from sqlalchemy.ext.declarative import declarative_base > > class ChildType(enum.Enum): > sub_1 = "sub_1" > sub_2 = "sub_2" > sub_3 = "sub_3" > > > class ParentModel(declarative_base()): > __table__ = "parent" > general_field = sa.Column(sa.String) > resource_type = sa.Column(sa.Enum(ChildType)) > > __mapper_args__ = { > "polymorphic_identity": "parent", > "polymorphic_on": resource_type, > } > > > class Sub1(ParentModel): > @sa.declared_attr > def child_value(cls): > return ParentModel.__table__.c.get( > "child_value", sa.Column(sa.Integer, nullable=True) > ) > > __mapper_args__ = {"polymorphic_identity": ChildType.sub_1} > > > class Sub2(ParentModel): > @sa.declared_attr > def child_value(cls): > return ParentModel.__table__.c.get( > "child_value", sa.Column(sa.Boolean, nullable=True) > ) > > __mapper_args__ = {"polymorphic_identity": ChildType.sub_2} > > > class Sub3(ParentModel): > @sa.declared_attr > def child_value(cls): > return ParentModel.__table__.c.get( > "child_value", sa.Column(ARRAY(MutableDict.as_mutable(HSTORE))) > ) > > __mapper_args__ = {"polymorphic_identity": ChildType.sub_3} > > > > e = create_engine("postgresql://scott:tiger@pg12/test", echo=True) > ParentModel.drop_all(e) > ParentModel.create_all(e) > s = Session(e) > > s.add(Sub3(child_value=[{"foo": "bar"}])) > s.commit() > > > > > On Fri, Aug 21, 2020, at 8:06 PM, Saakshaat Singh wrote: >> Hi, >> >> I'm working with SQLAlchemy and Postgres and I have a polymorphic model >> whose subclasses have a field with the same name. To allow this field to >> co-exist with the others and not cause any name conflicts, I'm using the >> `declare_attr` decorator from SQLAlchemy. >> >> This solution works well for fields consisting of primary data types, >> however when I try to use Postgres's HSTORE to store dictionary values, >> SQLAlchemy complains with: >> >> sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) can't adapt >> type 'dict' >> >> >> My guess is that this happens because `declared_attr` has constrains on >> which data types its fields have. >> >> Here's an example of how my models look: >> >> *import enum * >> ** >> *import sqlalchemy as sa* >> *from sqlalchemy.dialects.postgres import ARRAY, HSTORE* >> *from sqlalchemy.ext.mutables import MutableDict* >> ** >> *class ChildType(enum.Enum):* >> * sub_1 = "sub_1"* >> * sub_2 = "sub_2"* >> * sub_3 = "sub_3"* >> ** >> *class ParentModel(sa.declarative_base()):* >> * __table__ = 'parent'* >> * general_field = sa.Column(sa.String)* >> * r_type = sa.Column(sa.Enum(ChildType))* >> * * >> * __mapper_args__ = {* >> * 'polymorphic_identity': 'parent',* >> * 'polymorphic_on': resource_type* >> * }* >> * * >> * * >> *class Sub1(ParentModel):* >> * @sa.declared_attr* >> * def child_value(cls):* >> * return ParentModel.__table__.c.get('child_value', >> sa.Column(sa.Integer, nullable=True))* >> * * >> * __mapper_args__ = {* >> * 'polymorphic_identity': ChildType.sub_1* >> * }* >> * * >> *class Sub2(ParentModel):* >> * @sa.declared_attr* >> * def child_value(cls):* >> * return ParentModel.__table__.c.get('child_value', >> sa.Column(sa.Boolean, nullable=True))* >> * * >> * __mapper_args__ = {* >> * 'polymorphic_identity': ChildType.sub_2* >> * }* >> * * >> *class Sub3(ParentModel):* >> * @sa.declared_attr* >> * def child_value(cls):* >> * return ParentModel.__table__.c.get('child_value', >> sa.Column(ARRAY(MutableDict.as_mutable(HSTORE))))* >> * * >> * __mapper_args__ = {* >> * 'polymorphic_identity': ChildType.sub_3* >> * }* >> >> >> Can anyone help me out with a potential workaround/solution? >> >> Thanks! >> >> -- >> SQLAlchemy - >> The Python SQL Toolkit and Object Relational Mapper >> >> http://www.sqlalchemy.org/ >> >> To post example code, please provide an MCVE: Minimal, Complete, and >> Verifiable Example. See http://stackoverflow.com/help/mcve for a full >> description. >> --- >> 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 view this discussion on the web visit >> https://groups.google.com/d/msgid/sqlalchemy/0421937b-08f0-470d-8067-43430bfc1ca8n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/sqlalchemy/0421937b-08f0-470d-8067-43430bfc1ca8n%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/51688c7d-cca2-433a-8690-f0996ce5f8a7%40www.fastmail.com > > <https://groups.google.com/d/msgid/sqlalchemy/51688c7d-cca2-433a-8690-f0996ce5f8a7%40www.fastmail.com?utm_medium=email&utm_source=footer>. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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