How do I manage relationships in Flask ORM?

How do I manage relationships in Flask ORM?

In Flask ORM, you can manage relationships using SQLAlchemy. You define relationships in your models using the relationship() function.

Can you give me an example of a one-to-many relationship?

Sure! For a one-to-many relationship, you might have a User model and a Post model. A user can have multiple posts, so you would define it like this:

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    posts = db.relationship('Post', backref='author')

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))

What about many-to-many relationships?

For many-to-many relationships, you need an association table. For example, if you have Students and Courses, you can define it like this:

student_courses = db.Table('student_courses',
    db.Column('student_id', db.Integer, db.ForeignKey('student.id')),
    db.Column('course_id', db.Integer, db.ForeignKey('course.id'))
)

class Student(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    courses = db.relationship('Course', secondary=student_courses, backref='students')

class Course(db.Model):
    id = db.Column(db.Integer, primary_key=True)