One to One self-referentianship - Wrong mapping order
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I've got one sqlalchemy model, declared in such way:
class Cat(BaseModel): # BaseModel declares id and uuid field, also renames table to 'cats'
name = db.Column(db.String(256))
color= db.Column(db.String(256))
next_cat_id = db.Column(db.Integer(), db.ForeignKey('cats.id'))
next_cat = db.relationship("Cat", uselist=False)
So it should One-One rel. where previous cat points at the next one.
I prepared some dummy data in my postgres table:
id next_cat_id
1 2
2 3
3 4
4 5
5 Null
Problem comes out when I try to get object of the next cat:
cat = Cat.query.filter_by(id=5).first() # Gives cat with id=5 (OK)
> cat.next_cat_id # Gives None (OK)
> cat.next_cat # Gives cat with id=4 instead of None
I thing sqlalchemy have some troubles with resolving relationship direction. I tried also to specify remote_side parameter, but still same problem occurs.
python postgresql sqlalchemy
edited yesterday
Ilja Everilä
22.2k33359
asked yesterday
needtobe
12917
add a comment |
up vote
0
down vote
favorite
I've got one sqlalchemy model, declared in such way:
class Cat(BaseModel): # BaseModel declares id and uuid field, also renames table to 'cats'
name = db.Column(db.String(256))
color= db.Column(db.String(256))
next_cat_id = db.Column(db.Integer(), db.ForeignKey('cats.id'))
next_cat = db.relationship("Cat", uselist=False)
So it should One-One rel. where previous cat points at the next one.
I prepared some dummy data in my postgres table:
id next_cat_id
1 2
2 3
3 4
4 5
5 Null
Problem comes out when I try to get object of the next cat:
cat = Cat.query.filter_by(id=5).first() # Gives cat with id=5 (OK)
> cat.next_cat_id # Gives None (OK)
> cat.next_cat # Gives cat with id=4 instead of None
I thing sqlalchemy have some troubles with resolving relationship direction. I tried also to specify remote_side parameter, but still same problem occurs.
python postgresql sqlalchemy
edited yesterday
Ilja Everilä
22.2k33359
asked yesterday
needtobe
12917
settingremote_sideonnext_catfixed it for me:next_cat = db.relationship("Cat", uselist=False, remote_side=[id])
– SuperShoot
yesterday
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I've got one sqlalchemy model, declared in such way:
class Cat(BaseModel): # BaseModel declares id and uuid field, also renames table to 'cats'
name = db.Column(db.String(256))
color= db.Column(db.String(256))
next_cat_id = db.Column(db.Integer(), db.ForeignKey('cats.id'))
next_cat = db.relationship("Cat", uselist=False)
So it should One-One rel. where previous cat points at the next one.
I prepared some dummy data in my postgres table:
id next_cat_id
1 2
2 3
3 4
4 5
5 Null
Problem comes out when I try to get object of the next cat:
cat = Cat.query.filter_by(id=5).first() # Gives cat with id=5 (OK)
> cat.next_cat_id # Gives None (OK)
> cat.next_cat # Gives cat with id=4 instead of None
I thing sqlalchemy have some troubles with resolving relationship direction. I tried also to specify remote_side parameter, but still same problem occurs.
python postgresql sqlalchemy
edited yesterday
Ilja Everilä
22.2k33359
asked yesterday
needtobe
12917
I've got one sqlalchemy model, declared in such way:
class Cat(BaseModel): # BaseModel declares id and uuid field, also renames table to 'cats'
name = db.Column(db.String(256))
color= db.Column(db.String(256))
next_cat_id = db.Column(db.Integer(), db.ForeignKey('cats.id'))
next_cat = db.relationship("Cat", uselist=False)
So it should One-One rel. where previous cat points at the next one.
I prepared some dummy data in my postgres table:
id next_cat_id
1 2
2 3
3 4
4 5
5 Null
Problem comes out when I try to get object of the next cat:
cat = Cat.query.filter_by(id=5).first() # Gives cat with id=5 (OK)
> cat.next_cat_id # Gives None (OK)
> cat.next_cat # Gives cat with id=4 instead of None
I thing sqlalchemy have some troubles with resolving relationship direction. I tried also to specify remote_side parameter, but still same problem occurs.
python postgresql sqlalchemy
python postgresql sqlalchemy
edited yesterday
Ilja Everilä
22.2k33359
asked yesterday
needtobe
12917
edited yesterday
Ilja Everilä
22.2k33359
asked yesterday
needtobe
12917
edited yesterday
Ilja Everilä
22.2k33359
edited yesterday
Ilja Everilä
22.2k33359
edited yesterday
Ilja Everilä
22.2k33359
22.2k33359
asked yesterday
needtobe
12917
asked yesterday
needtobe
12917
asked yesterday
needtobe
12917
12917
settingremote_sideonnext_catfixed it for me:next_cat = db.relationship("Cat", uselist=False, remote_side=[id])
– SuperShoot
yesterday
add a comment |
settingremote_sideonnext_catfixed it for me:next_cat = db.relationship("Cat", uselist=False, remote_side=[id])
– SuperShoot
yesterday
setting
remote_side on next_cat fixed it for me: next_cat = db.relationship("Cat", uselist=False, remote_side=[id])– SuperShoot
yesterday
setting
remote_side on next_cat fixed it for me: next_cat = db.relationship("Cat", uselist=False, remote_side=[id])– SuperShoot
yesterday
add a comment |
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setting
remote_sideonnext_catfixed it for me:next_cat = db.relationship("Cat", uselist=False, remote_side=[id])– SuperShoot
yesterday