HI,
I m currently trying to vertical partition my database and I have
split it into two groups of tables (say { documents, table1, table2 }
and { table3 }.
So I have
s_engine = create_engine(t_database_string)#, echo=True)
#echo="debug")#, echo=True)
t_engine = create_engine(t_database_string)
Base = declarative_base()
metadata = Base.metadata
documents = Table("documents', metadata,
Column("document_id", Integer, primary_key = True),
}
table1 = Table("table1", metadata,
Column("interval_id", Integer, primary_key=True),
Column("document_id", Integer,
ForeignKey("documents.document_id")),
)
table3 = Table("table3", metadata,
Column("foo_id", Integer, primary_key = True),
)
table2 = Table("table2", metadata,
Column("id", Integer, primary_key = True),
Column("interval_id", Integer, ForeignKey("table1.interval__id"))
Column("foo_id", Integer, ForeignKey("table3.foo_id"))
)
secondary = table1.join(table2,
onclause=table1.c.interval_id==table2.c.interval_id).alias("spe_join")
table3.create(bind=t_engine)
........ etc
mapper(Foo, table3)
mapper(Document, documents_table, properties={
"foos":relation(Foo,
primaryjoin=documents_table.c.document_id ==
secondary.c.intervals_document_id,
secondaryjoin=secondary.c.table2_foo_id == table3.c.foo_id,
viewonly = True,
secondary=secondary)
})
session = sessionmaker(binds={Document:s_engine, Foo:t_engine})
however what happens is that it complains about the foos relation in
that it says that
sqlalchemy.exc.ArgumentError: Could not determine relation direction
for secondaryjoin condition 'spe_join.table2_foo_id = foo.foo_id', on
relation Document.foos. Specify the foreign_keys argument to indicate
which columns on the relation are foreign.
When I had all the tables in the same database I had no problems
involving having to specify foreign keys. What does SQLalchemy do it
the background here? Is my problem that it doesnt know that table3 is
accessed via the t_engine. How can I make it explicitly know this
here? I have tried using different metadata bindings but to no good.
Any pointers/help would be greatly appreciated?
Nathan
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to sqlalchemy@googlegroups.com
To unsubscribe from this group, send email to
sqlalchemy+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en
-~----------~----~----~----~------~----~------~--~---
