Re: [sqlalchemy] self-referential relationship w/ declarative style
On Feb 20, 2011, at 10:12 PM, Ryan wrote:
I'm attempting a self-referential mapping on a Client object that includes
these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style. Thanks!
the last example in the section
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
illustrates a declarative self-referential relationship. Note that the id
Column object can be referenced directly when you're inside the class
declaration itself.
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Re: [sqlalchemy] self-referential relationship w/ declarative style
On Feb 22, 2011, at 9:03 PM, Ryan McKillen wrote:
Mike, thanks a lot. Big help. I'm almost there.
This seems to do the trick:
usersid = Column(Integer, primary_key=True, key='id')
inviter_id = Column(Integer, ForeignKey('users.id'))
inviter = relationship('User',
uselist = False,
backref = backref('invitee', remote_side=usersid, uselist=True),
)
When there are two users, one being the inviter (parent) and the other being
the invitee (child), it works like a charm:
self.assertEqual(invitee1.inviter.id, inviter.id)
self.assertEqual(inviter.invitee[0].id, invitee1.id)
But add a third user, one being the inviter and two being the invitees,
invitee1.inviter is None.
probably because of that uselist=False, which makes it into a one-to-one.
Adjacency list is a standard single foreign key relationship - one-to-many on
one side, many-to-one on the other.
There's an illustration of exactly how the data resides in the table:
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
Any ideas for me?
On Tue, Feb 22, 2011 at 7:54 AM, Michael Bayer mike...@zzzcomputing.com
wrote:
On Feb 20, 2011, at 10:12 PM, Ryan wrote:
I'm attempting a self-referential mapping on a Client object that includes
these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style.
Thanks!
the last example in the section
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
illustrates a declarative self-referential relationship. Note that the id
Column object can be referenced directly when you're inside the class
declaration itself.
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Re: [sqlalchemy] self-referential relationship w/ declarative style
I added that in because without it I get:
TypeError: Incompatible collection type: User is not list-like
On Tue, Feb 22, 2011 at 6:47 PM, Michael Bayer mike...@zzzcomputing.comwrote:
On Feb 22, 2011, at 9:03 PM, Ryan McKillen wrote:
Mike, thanks a lot. Big help. I'm almost there.
This seems to do the trick:
usersid = Column(Integer, primary_key=True, key='id')
inviter_id = Column(Integer, ForeignKey('users.id'))
inviter = relationship('User',
uselist = False,
backref = backref('invitee', remote_side=usersid, uselist=True),
)
When there are two users, one being the inviter (parent) and the other
being the invitee (child), it works like a charm:
self.assertEqual(invitee1.inviter.id, inviter.id)
self.assertEqual(inviter.invitee[0].id, invitee1.id)
But add a third user, one being the inviter and two being the invitees,
invitee1.inviter is None.
probably because of that uselist=False, which makes it into a one-to-one.
Adjacency list is a standard single foreign key relationship - one-to-many
on one side, many-to-one on the other.
There's an illustration of exactly how the data resides in the table:
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
Any ideas for me?
On Tue, Feb 22, 2011 at 7:54 AM, Michael Bayer
mike...@zzzcomputing.comwrote:
On Feb 20, 2011, at 10:12 PM, Ryan wrote:
I'm attempting a self-referential mapping on a Client object that includes
these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no
luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style.
Thanks!
the last example in the section
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationshipsillustrates
a declarative self-referential relationship. Note that the id
Column object can be referenced directly when you're inside the class
declaration itself.
--
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Re: [sqlalchemy] self-referential relationship w/ declarative style
one side scalar, one side collection. the collection side you use .append().
You decide which end is the non-collection by setting remote_side, in your
code below its invitee.
On Feb 22, 2011, at 9:59 PM, Ryan McKillen wrote:
I added that in because without it I get:
TypeError: Incompatible collection type: User is not list-like
On Tue, Feb 22, 2011 at 6:47 PM, Michael Bayer mike...@zzzcomputing.com
wrote:
On Feb 22, 2011, at 9:03 PM, Ryan McKillen wrote:
Mike, thanks a lot. Big help. I'm almost there.
This seems to do the trick:
usersid = Column(Integer, primary_key=True, key='id')
inviter_id = Column(Integer, ForeignKey('users.id'))
inviter = relationship('User',
uselist = False,
backref = backref('invitee', remote_side=usersid, uselist=True),
)
When there are two users, one being the inviter (parent) and the other being
the invitee (child), it works like a charm:
self.assertEqual(invitee1.inviter.id, inviter.id)
self.assertEqual(inviter.invitee[0].id, invitee1.id)
But add a third user, one being the inviter and two being the invitees,
invitee1.inviter is None.
probably because of that uselist=False, which makes it into a one-to-one.
Adjacency list is a standard single foreign key relationship - one-to-many on
one side, many-to-one on the other.
There's an illustration of exactly how the data resides in the table:
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
Any ideas for me?
On Tue, Feb 22, 2011 at 7:54 AM, Michael Bayer mike...@zzzcomputing.com
wrote:
On Feb 20, 2011, at 10:12 PM, Ryan wrote:
I'm attempting a self-referential mapping on a Client object that includes
these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style.
Thanks!
the last example in the section
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
illustrates a declarative self-referential relationship. Note that the
id Column object can be referenced directly when you're inside the class
declaration itself.
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Re: [sqlalchemy] self-referential relationship w/ declarative style
Got it. Many thanks!
On Tue, Feb 22, 2011 at 7:02 PM, Michael Bayer mike...@zzzcomputing.comwrote:
one side scalar, one side collection. the collection side you use
.append(). You decide which end is the non-collection by setting
remote_side, in your code below its invitee.
On Feb 22, 2011, at 9:59 PM, Ryan McKillen wrote:
I added that in because without it I get:
TypeError: Incompatible collection type: User is not list-like
On Tue, Feb 22, 2011 at 6:47 PM, Michael Bayer
mike...@zzzcomputing.comwrote:
On Feb 22, 2011, at 9:03 PM, Ryan McKillen wrote:
Mike, thanks a lot. Big help. I'm almost there.
This seems to do the trick:
usersid = Column(Integer, primary_key=True, key='id')
inviter_id = Column(Integer, ForeignKey('users.id'))
inviter = relationship('User',
uselist = False,
backref = backref('invitee', remote_side=usersid, uselist=True),
)
When there are two users, one being the inviter (parent) and the other
being the invitee (child), it works like a charm:
self.assertEqual(invitee1.inviter.id, inviter.id)
self.assertEqual(inviter.invitee[0].id, invitee1.id)
But add a third user, one being the inviter and two being the invitees,
invitee1.inviter is None.
probably because of that uselist=False, which makes it into a one-to-one.
Adjacency list is a standard single foreign key relationship -
one-to-many on one side, many-to-one on the other.
There's an illustration of exactly how the data resides in the table:
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
Any ideas for me?
On Tue, Feb 22, 2011 at 7:54 AM, Michael Bayer
mike...@zzzcomputing.comwrote:
On Feb 20, 2011, at 10:12 PM, Ryan wrote:
I'm attempting a self-referential mapping on a Client object that
includes these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no
luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style.
Thanks!
the last example in the section
http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationshipsillustrates
a declarative self-referential relationship. Note that the id
Column object can be referenced directly when you're inside the class
declaration itself.
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[sqlalchemy] self-referential relationship w/ declarative style
I'm attempting a self-referential mapping on a Client object that includes
these two columns:
id = Column(Integer, primary_key=True)
inviter_id = Column(Integer, ForeignKey('users.id'), nullable=True)
Started here with no luck:
inviter = relationship('Client', primaryjoin='Client.id ==
Client.inviter_id', uselist=False)
Then read about self-referential mapping in the docs and tried with no luck:
inviter = relationship('Client', remote_side='Client.id', uselist=False)
And this with an error:
relationship('Client', remote_side=[Client.id], uselist=False)
Would be a great help to see how this is done in a declarative style.
Thanks!
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