SqlAlchemy error: Foreign key could not find table - mysql

Question

So I'm building an app and I'm trying to save new changes to my database but when I try to commit the changes in the flask using db.session.commit() it returns me the following error:
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'products.country_id' could not find table 'countries' with which to generate a foreign key to target column 'id'
In my models.py I have the following:
from app import db
from . import db
from datetime import datetime
def now():
return datetime.now()
class Countries(db.Model):
__tablename__ = 'countries'
__table_args__ = {'schema': 'products_data'}
id = db.Column(db.Integer, primary_key=True, unique=True, autoincrement=True)
name = db.Column(db.String(255))
code = db.Column(db.String(45))
def __repr__(self):
return f'Id {self.id}'
class Categories(db.Model):
__tablename__ = 'categories'
__table_args__ = {'schema': 'products_data'}
id = db.Column(db.Integer, primary_key=True, unique=True, autoincrement=True)
name = db.Column(db.String(255))
def __repr__(self):
return f'Id {self.id}'
class Brands(db.Model):
__tablename__ = 'brands'
__table_args__ = {'schema': 'products_data'}
id = db.Column(db.Integer, primary_key=True, unique=True, autoincrement=True)
name = db.Column(db.String(255))
logo = db.Column(db.String(5000))
feed = db.Column(db.String(5000))
feed_type = db.Column(db.String(45))
category_id = db.Column(db.Integer, db.ForeignKey('categories.id'))
country_id = db.Column(db.Integer, db.ForeignKey('countries.id'))
awinmid = db.Column(db.Integer)
def __repr__(self):
return f'Id {self.id}'
class Products(db.Model):
__tablename__ = 'products'
__table_args__ = {'schema': 'products_data'}
id = db.Column(db.Integer, primary_key=True, unique=True, autoincrement=True)
name = db.Column(db.String(255))
url = db.Column(db.Text)
category_id = db.Column(db.Integer, db.ForeignKey('categories.id'))
country_id = db.Column(db.Integer, db.ForeignKey('countries.id'))
price = db.Column(db.Float)
currency = db.Column(db.String(45))
discount_price = db.Column(db.Float)
shipping = db.Column(db.Float)
brand_id = db.Column(db.Integer, db.ForeignKey('brands.id'))
Am I doing anything wrong when associating a column in products with a foreign key? This is the first time I encounter this error so I'm really lost on what to do right now.

Answer 1

To fix I just added the schema to the db.ForeignKey and it worked
Example:
db.ForeignKey('products_data.countries.id')
PS:
Not my idea. Just wanted to post the answer in case someone visits the post later with the same problem.
Gord Thompson thanks for the help!

Answer 2

First of all, I don t see any table Categories. Secondly, you copy pasted your schema from the Products table into your Countries one.
PS: By default sqlalchemy gives the tables the name of the class (lower cased). So your __tablename__='products' does nothing actually.
EDIT:
The problem with your code lies in how you set the __table_args__ attribute. You assign an object to it, which by their specifications is wrong.
Take a look at the following example and modify your code accordingly
__table_args__ = ({'schema': 'products_data'})
Also for further reference, take a look at this https://docs.sqlalchemy.org/en/13/orm/extensions/declarative/table_config.html