Sequelize model references vs associations

Question

Just starting to use Sequelize and I've setup a bunch of models and seeds, but I can't figure out references vs associations. I don't see the use case for references if they even do what I think they do, but I couldn't find a good explanation in the docs.

Is this redundant having references and associations?

module.exports = (sequelize, DataTypes) => {
  const UserTask = sequelize.define('UserTask',
    {
      id: {
        primaryKey: true,
        type: DataTypes.UUID,
        defaultValue: DataTypes.UUIDV4
      },
      userId: {
        type: DataTypes.UUID,
        references: { // <--- is this redundant to associate
          model: 'User',
          key: 'id'
        }
      }
      // ... removed for brevity
    },
    {
      classMethods: {
        associate: models => { <--- makes references redundant?
          UserTask.belongsTo(models.User, {
            onDelete: 'CASCADE',
            foreignKey: {
              fieldName: 'userId',
              allowNull: true,
              require: true
            },
            targetKey: 'id'
          });
        }
      }
    }
  );
  return UserTask;
};

Answer 1

Using references you create a reference to another table, without adding any constraints, or associations. Which means that is just a way of signaling the database that this table has a reference to another.

Creating an association will add a foreign key constraint to the attributes. And the you can perform all the magic behind it the association functions. i.e User.getTasks();

More info about references here: https://sequelize.readthedocs.io/en/latest/docs/associations/#foreign-keys_1

About association here: http://docs.sequelizejs.com/manual/tutorial/associations.html