nodejs 续集 hasOne 关联不起作用

Question

in my nodejs app where i am using sequelize to reach to database i have some tables called (Products , Users , Carts , CartItems)

and there is this relationship between them

Product.belongsTo(User, { constraints: true, onDelete: 'CASCADE' });
User.hasMany(Product);
User.hasOne(Cart);
Cart.belongsTo(User);
Cart.belongsToMany(Product, { through: CartItem });
Product.belongsToMany(Cart, { through: CartItem });

as you see user can only have one cart but where i use createCart(); function it can make more than one carts

sequelize
// .sync({ force: true })
    .sync()
    .then(result => {
        return User.findByPk(1);
        // console.log(result);
    })
    .then(user => {
        if (!user) {
            return User.create({ name: 'Max', email: 'test@test.com' });
        }
        return user;
    })
    .then(user => {
        // console.log(user);
        return user.createCart();
    })
    .then(cart => {
        app.listen(4000);
    })
    .catch(err => {
        console.log(err);
    });

this code is in my app.js file and every time server reloads it checks if there is not a user it makes it but createCart(); which sequelize should handle that to not be more than one cart for each user , that doesn't works correctly and everytime server reloads it makes another cart for user

Answer 1

Is the id of user a unique key or primary key in your cart table? i think it should be, and your keys should be defined in those relationships i think... something like so..

User.hasOne(Cart, { as: 'Cart', sourceKey: 'id', foreignKey: 'user_id' }); Cart.belongsTo(User, { as: 'CartOwner', sourceKey: 'user_id', foreignKey: 'id' });