How to have two attributes, together, be unique?-CodePudding

I have a user class which looks like this:

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    first_name = db.Column(db.String(15), unique=True, nullable=False)
    last_name = db.Column(db.String(15), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)

    def __repr__(self):
        return f"User('{self.first_name}', '{self.last_name}', '{self.email}')"

As you can see, first_name and last_name have to be unique, but that's not really what I want. Instead, I'd like the full name to be unique, so first_name and last_name together has to be unique. How can I do that?

CodePudding user response：

You can use a Declarative Table Configuration and define a UNIQUE constraint. However, keep in mind that there can be several people with the same first and last name combination.

class User(db.Model, UserMixin):
     __table_args__ = (db.UniqueConstraint('first_name', 'last_name'),)
    id = db.Column(db.Integer, primary_key=True)
    first_name = db.Column(db.String(15), nullable=False)
    last_name = db.Column(db.String(15), nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)

    def __repr__(self):
        return f"User('{self.first_name}', '{self.last_name}', '{self.email}')"