NameError - FLASK SQLACHEMY - Reusing Database Models i.e. Columns

Question

I'm trying to reuse database table classes /models

my model is as below restmodels.py

 # attributes master - holds the main product attributes
class AttributesMst(db.Model):
    __tablename__ = 'oc_attribute'
    attribute_id = db.Column(db.INT, primary_key=True, autoincrement=True, nullable=False)
    attribute_group_id = AttributesGroups.attribute_group_id
    sort_order = db.Column(db.INT, nullable=False)


#Attribute Groups
class AttributesGroups(db.Model):
    __tablename__ = 'oc_attribute_group'
    attribute_group_id = db.Column(db.INT, primary_key=True, autoincrement=True, nullable=False)
    sort_order = db.Column(db.INT, nullable=False)



# attribute descriptions and language
class AttributesDescrptn(db.Model):
    __tablename__ = 'oc_attribute_description'
    attribute_id = AttributesMst.attribute_id
    language_id = db.Column(db.INT, primary_key=True, autoincrement=False, nullable=False)
    name = db.Column(db.VARCHAR(64), nullable=False)

When I run the code I get the following Traceback.

Traceback (most recent call last):
  File "/home/seroney/PycharmProjects/TestProject/Addresses/restmodels.py", line 108, in <module>
    class AttributesMst(db.Model):
  File "/home/seroney/PycharmProjects/TestProject/Addresses/restmodels.py", line 111, in AttributesMst
    attribute_group_id = AttributesGroups.attribute_group_id
NameError: name 'AttributesGroups' is not defined

Please note the classes are in the same file. Regards.

What I'm trying to achieve is reuse a table column like on Play Framework.

Answer 1

You define AttributesGroups after you reference it. That is why you get the NameError . In the end, however, I think you're trying to create a foreign key. (Having new used Play Framework, though, I could be wrong.)

To create a foreign key with SQLAlchemy, replace

attribute_group_id = AttributesGroups.attribute_group_id

with

attribute_group_id = db.Column(db.Integer, db.ForeignKey('oc_attribute_groups.attribute_group_id'))