Hi Simon,
I've read and I've tried a number of what is written but I still can't
solve it.
I've done this:
class RelationshipsModel(db.Model):
__tablename__ = 'relationships'
source_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
target_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
strength = db.Column(db.Integer, nullable=False)
source_node = relationship("NodesModel")
target_node = relationship("NodesModel")
class NodesModel(db.Model):
__tablename__ = 'nodes'
id = db.Column(db.BigInteger, primary_key=True)
project_uuid = db.Column(UUID(as_uuid=True),
db.ForeignKey('projects.uuid'))
name = db.Column(db.String(50), nullable=False)
size = db.Column(db.Integer, nullable=False)
posts_nodes = relationship("PostsNodesModel", backref="nodes")
Below are all that I"ve tried.
-----
class RelationshipsModel(db.Model):
__tablename__ = 'relationships'
source_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
target_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
strength = db.Column(db.Integer, nullable=False)
source_node = relationship("NodesModel")
target_node = relationship("NodesModel")
class NodesModel(db.Model):
__tablename__ = 'nodes'
id = db.Column(db.BigInteger, primary_key=True)
project_uuid = db.Column(UUID(as_uuid=True),
db.ForeignKey('projects.uuid'))
name = db.Column(db.String(50), nullable=False)
size = db.Column(db.Integer, nullable=False)
posts_nodes = relationship("PostsNodesModel", backref="nodes")
relationships_s = relationship("RelationshipsModel",
foreign_keys=["relationships.source_node_id"], backref="nodes")
relationships_t = relationship("RelationshipsModel",
foreign_keys=["relationships.target_node_id"], backref="nodes")
-----
class RelationshipsModel(db.Model):
__tablename__ = 'relationships'
source_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
target_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
strength = db.Column(db.Integer, nullable=False)
class NodesModel(db.Model):
__tablename__ = 'nodes'
id = db.Column(db.BigInteger, primary_key=True)
project_uuid = db.Column(UUID(as_uuid=True),
db.ForeignKey('projects.uuid'))
name = db.Column(db.String(50), nullable=False)
size = db.Column(db.Integer, nullable=False)
posts_nodes = relationship("PostsNodesModel", backref="nodes")
relationships_s = relationship("RelationshipsModel",
foreign_keys=["relationships.source_node_id"], backref="nodes")
relationships_t = relationship("RelationshipsModel",
foreign_keys=["relationships.target_node_id"], backref="nodes")
-----
class RelationshipsModel(db.Model):
__tablename__ = 'relationships'
source_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
target_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
primary_key=True)
strength = db.Column(db.Integer, nullable=False)
class NodesModel(db.Model):
__tablename__ = 'nodes'
id = db.Column(db.BigInteger, primary_key=True)
project_uuid = db.Column(UUID(as_uuid=True),
db.ForeignKey('projects.uuid'))
name = db.Column(db.String(50), nullable=False)
size = db.Column(db.Integer, nullable=False)
posts_nodes = relationship("PostsNodesModel", backref="nodes")
relationships_s = relationship("RelationshipsModel",
foreign_keys=["relationships.source_node_id"], backref="nodes")
relationships_t = relationship("RelationshipsModel",
foreign_keys=["relationships.target_node_id"], backref="nodes")
I've also tried using
relationships = relationship("RelationshipsModel",
foreign_keys="[NodesModel.source_node_id,
NodesModel.target_node_id]",
backref="nodes")
Any other codes that I haven't tried?
Desmond
On Wed, 29 May 2019 at 17:30, Simon King <[email protected]> wrote:
> On Wed, May 29, 2019 at 10:08 AM Desmond Lim <[email protected]> wrote:
> >
> > Hi there,
> >
> > I'm been puzzling over this and still can't find answer.
> >
> > I have 2 tables:
> >
> > Nodes:
> >
> > class NodesModel(db.Model):
> > __tablename__ = 'nodes'
> >
> > id = db.Column(db.BigInteger, primary_key=True)
> > project_uuid = db.Column(UUID(as_uuid=True),
> db.ForeignKey('projects.uuid'))
> > name = db.Column(db.String(50), nullable=False)
> > size = db.Column(db.Integer, nullable=False)
> >
> > posts_nodes = relationship("PostsNodesModel", backref="nodes")
> > relationships = relationship("RelationshipsModel", backref="nodes")
> >
> > Relationships:
> >
> > class RelationshipsModel(db.Model):
> > __tablename__ = 'relationships'
> >
> > source_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
> primary_key=True)
> > target_node_id = db.Column(db.BigInteger, db.ForeignKey('nodes.id'),
> primary_key=True)
> > strength = db.Column(db.Integer, nullable=False)
> >
> > I'm getting errors on this line:
> >
> > relationships = relationship("RelationshipsModel", backref="nodes")
> >
> > And I know it is because my Relationships table has the Nodes table as a
> foreign key twice. But I have not idea how do I create 2 relationships to
> the Relationships table?
> >
>
> I assume the error you are getting is something like "Could not
> determine join condition..."? In which case, you probably need this
> section of the docs:
>
>
> https://docs.sqlalchemy.org/en/13/orm/join_conditions.html#handling-multiple-join-paths
>
> Hope that helps,
>
> Simon
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
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--
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.
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