w...@nobleenergyinc.com wrote:
> Here's the issue, boiled down to one file. On import, the last statement
> fails, mapping the Connections object. I just need to map two relations on
> an association object (Connections) to a polymorphic union (NetworkNode).
> Is there a way to do this?
your "foreign_keys" is outside of "downstreamnodes" and is being set up as
a relationship() of its own. corrected:
connmapper = orm.mapper(Connection,cnct,properties=dict(
upstreamnodes=orm.relation(NetworkNode,primaryjoin=
and_(cnct.c.downstream_id==nn.c.node_id,
cnct.c.downstream_type==nn.c.node_type),
foreign_keys=[nn.c.node_id,nn.c.node_type]),
downstreamnodes=orm.relation(NetworkNode,primaryjoin=
and_(cnct.c.upstream_id==nn.c.node_id,
cnct.c.upstream_type==nn.c.node_type),
foreign_keys=[nn.c.node_id,nn.c.node_type]),
))
>
> sqlalchemy.exc.ArgumentError: Column 'network_nodes.node_id' is not
> represented in mapper's table. Use the `column_property()` function to
> force this column to be mapped as a read-only attribute.
>
> from sqlalchemy import *
> from sqlalchemy import sql
> from sqlalchemy import orm
>
> metadata = MetaData()
>
> tbl1 = Table("source_sink",metadata,
> Column("node_id",Integer,primary_key=True),
> Column("source_sink_name",String(60),nullable=False),
> Column("source_or_sink",String(6)))
> tbl2 = Table("meas_type_a",metadata,
> Column("node_id",Integer,primary_key=True),
> Column("meas_point_name",String(60),nullable=False),
> Column("subtype",String(10)),
> Column("latitude",Numeric(precision=12,scale=9,asdecimal=True)),
> Column("longitude",Numeric(precision=12,scale=9,asdecimal=True)))
> tbl3 = Table("meas_type_b",metadata,
> Column("node_id",Integer,primary_key=True),
> Column("meas_point_name",String(60),nullable=False),
> Column("subtype",String(10)),
> Column("latitude",Numeric(precision=12,scale=9,asdecimal=True)),
> Column("longitude",Numeric(precision=12,scale=9,asdecimal=True)),
> Column("capacity",Numeric(precision=6,scale=2,asdecimal=True)))
> tbl4 = Table("meas_type_c",metadata,
> Column("node_id",Integer,primary_key=True),
> Column("meas_point_name",String(60),nullable=False),
> Column("subtype",String(10)),
> Column("latitude",Numeric(precision=12,scale=9,asdecimal=True)),
> Column("longitude",Numeric(precision=12,scale=9,asdecimal=True)),
> Column("stringuserfield1",String(40)),
>
> Column("numericuserfield1",Numeric(precision=6,scale=2,asdecimal=True)))
> nn = orm.util.polymorphic_union({1:tbl1,2:tbl2,3:tbl3,4:tbl4},
> "node_type","network_nodes")
> cnct = Table("connections",metadata,
> Column("upstream_id",Integer,primary_key=True),
> Column("upstream_type",Integer,primary_key=True),
> Column("downstream_id",Integer,primary_key=True),
> Column("downstream_type",Integer,primary_key=True),
> Column("effective_date",DateTime(timezone=False)),
> Column("expiration_date",DateTime(timezone=False)))
> class NetworkNode(object):
> pass
>
> nnmapper =
> orm.mapper(NetworkNode,nn,primary_key=[nn.c.node_id,nn.c.node_type],
> with_polymorphic=('*',nn),polymorphic_on=nn.c.node_type)
>
> class SourceSinkNode(NetworkNode):
> pass
> ss =
> orm.mapper(SourceSinkNode,tbl1,inherits=nnmapper,polymorphic_identity=1,concrete=True)
> class MeasTypeA(NetworkNode):
> pass
> ma =
> orm.mapper(MeasTypeA,tbl2,inherits=nnmapper,polymorphic_identity=2,concrete=True)
> class MeasTypeB(NetworkNode):
> pass
> mb =
> orm.mapper(MeasTypeB,tbl3,inherits=nnmapper,polymorphic_identity=3,concrete=True)
> class MeasTypeC(NetworkNode):
> pass
> mc =
> orm.mapper(MeasTypeC,tbl4,inherits=nnmapper,polymorphic_identity=4,concrete=True)
> class Connection(NetworkNode):
> pass
>
> connmapper = orm.mapper(Connection,cnct,properties=dict(
> upstreamnodes=orm.relation(NetworkNode,primaryjoin=
> and_(cnct.c.downstream_id==nn.c.node_id,
> cnct.c.downstream_type==nn.c.node_type),
> foreign_keys=[nn.c.node_id,nn.c.node_type]),
> downstreamnodes=orm.relation(NetworkNode,primaryjoin=
> and_(cnct.c.upstream_id==nn.c.node_id,
> cnct.c.upstream_type==nn.c.node_type)),
> foreign_keys=[nn.c.node_id,nn.c.node_type]))
>
> Wes Dyk
>
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