class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(50))
body = db.Column(db.Text)
comments = db.relationship('Comment',
back_populates='post',
cascade='all, delete-orphan') # collection
class Writer(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64))
books = db.relationship('Book', back_populates='writer')
# optional
def __repr__(self):
return f'Writer <id={self.id}, name={self.name}>'
class Capital(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(30), unique=True)
country_id = db.Column(db.Integer, db.ForeignKey('country.id'))
country = db.relationship('Country', back_populates='capital')
# optional
def __repr__(self):
return f'Capital <id={self.id}, name={self.name}, country={self.country.name if self.country else None}>'
class Citizen(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(30), unique=True)
city_id = db.Column(db.Integer, db.ForeignKey('city.id'))
city = db.relationship('City') # scalar
# optional
def __repr__(self):
return f'Citizen <id={self.id}, name={self.name}>'
class Book(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(64), index=True)
writer_id = db.Column(db.Integer, db.ForeignKey('writer.id'))
writer = db.relationship('Writer', back_populates='books')
# optional
def __repr__(self):
return f'Book <id={self.id}, title={self.title}>'
class Author(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64))
phone = db.Column(db.String(32), unique=True)
articles = db.relationship('Article')
# optional
def __repr__(self):
return f'Author <id={self.id}, name={self.name}, phone={self.phone}>'
class Country(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(30), unique=True)
capital = db.relationship('Capital',
uselist=False,
back_populates='country')
# optional
def __repr__(self):
return f'Country <id={self.id}, name={self.name}, capital=[{self.capital}]>'
class Teacher(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
office = db.Column(db.String(20))
students = db.relationship('Student',
secondary=student_teacher_table,
back_populates='teachers')
def __repr__(self):
return f'Teacher <id={self.id}, name={self.name}>'
class Comment(db.Model):
id = db.Column(db.Integer, primary_key=True)
body = db.Column(db.Text)
post_id = db.Column(db.Integer, db.ForeignKey('post.id'))
post = db.relationship('Post', back_populates='comments') # scalar