A mixin can add specific fields to another model in Flask,
Example model
# User Class class User(db.Model): __tablename__ = 'User' id = db.Column(Integer, primary_key=True) username = db.Column(String(32), unique=True) email = db.Column(String(32), unique=True) password = db.Column(Binary) role = db.Column(String(32), default="Member") # Define the relationship to Role via UserRoles def __init__(self, **kwargs): for property, value in kwargs.items(): # depending on whether value is an iterable or not, we must # unpack it's value (when **kwargs is request.form, some values [...]