Issue when creating on-to-many relationships in SQLAlchemy database - flask-sqlalchemy

Question

I created a Flask app with a database, with following classes:
db = SQLAlchemy(app)
class Category(db.Model):
__tablename__ = 'Category'
children = relationship("Child")
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.Text())
icon = db.Column(db.Text())
subcategories = db.relationship('Subcategory', backref="category")
def __init__(self, name, subcategories, icon):
self.name = name
self.color = icon
self.subcategories = subcategories
class Subcategory(db.Model):
__tablename__ = 'Subcategory'
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.Text())
color = db.Column(db.Text())
reward_points = db.Column(db.Integer())
category = db.Column(db.Text())
tasks = db.relationship('Task', backref="subcategory")
category_id = db.Column(db.Integer, db.ForeignKey('category.id'))
def __init__(self, name, color, reward_points, category, tasks, category_id):
self.name = name
self.color = color
self.reward_points = reward_points
self.category = category
self.tasks = tasks
self.category_id = category_id
class Task(db.Model):
__tablename__ = 'Task'
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
task = db.Column(db.Text())
start = db.Column(db.DateTime())
end = db.Column(db.DateTime())
duration = db.Column(db.Integer)
scheduled = db.Column(db.DateTime())
created = db.Column(db.DateTime())
status = db.Column(db.Text())
category = db.Column(db.Text())
subcategory = db.Column(db.Text())
tags = db.Column(db.Text())
subcategory_id = db.Column(db.Integer, db.ForeignKey('subcategory.id'))
def __init__(self, task, start, end, duration, category, subcategory, tags, created, status, scheduled, subcategory_id):
self.task = task
self.start = start
self.end = end
self.duration = duration
self.category = category
self.subcategory = subcategory
self.tags = tags
self.created = created
self.status = status
self.scheduled = scheduled
self.subcategory_id = subcategory_id
My goal is to create one to many relationships between the classes. I am trying to run the db.create_all() command, but am getting following error:
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'Subcategory.category_id' could not find table 'category' with which to generate a foreign key to target column 'id'
What am I doing wrong? Other questions on Stackoverflow with similar issues did not resolve my error.

Answer 1

Changing
category_id = db.Column(db.Integer, db.ForeignKey('category.id'))
to
category_id = db.Column(db.Integer, db.ForeignKey('Category.id'))
solved the issue.
Changing "category.id" to "category.c.id" solved the issue as well. If anyone knows why, pls let me know ;-)