Sequelize Eager Loading Error when including related model

Question

I\'m using Sequelize to make this request:

return Expense.findAll({
     include: [{
       model: ExpenseCategory
     }],
   })
  .then(expenses => res.stat         


        

Answer 1

I got an working answer. In this example i have a scheme where a department can have a lot of positions. The Position will include the department and the department will include its positions.

models/Department.js

module.exports = (sequelize, DataTypes) => 
{
const Sequelize = require('sequelize');
const Department = sequelize.define('Department', 
{
    ...
}
Department.associate = function(models) {
    Department.hasMany(models.Position, {
      foreignKey: 'department_id',
      as: 'positions'
    });
};

return Department;
};

models/Position.js

module.exports = (sequelize, DataTypes) => 
{
const Sequelize = require('sequelize');
const Position = sequelize.define('Position', 
{
    ...
}

Position.associate = function(models) {
    Position.belongsTo(models.Department, {
        foreignKey: 'department_id',
        as: 'department',
        onDelete: 'CASCADE'
    });
};

return Position;
};

controllers/departmentController.js

exports.all = async function(req, res)
{
return Department
    .findAll({include: [ 'positions' ]})
    .then((data) => {
        if (!data) { return res.status(400).json({status: 400,message: 'Registro não encontrado', data: data }); }
        return res.status(200).json(data);
    })
    .catch((error) => {
        return res.status(400).json({message: 'Falha no banco de dados.', data: error})
    });
};

controllers/positionController.js

exports.all = async function(req, res)
{
return Position
    .findAll({include: [ 'department' ]})
    .then((data) => {
        if (!data) { return res.status(400).json({status: 400,message: 'Registro não encontrado', data: data }); }
        return res.status(200).json(data);
    })
    .catch((error) => {
        console.log(error);
        return res.status(400).json({message: 'Falha no banco de dados.', data: error})
    });
};

Answer 2

Just change this sections

classMethods: {
    associate: function (models) {
        ExpenseCateogory.hasMany(models.Expense, {
            foreignKey: 'expenseCategoryId'
        });
    }
}

to

ExpenseCategory.associate = (models) => {
    ExpenseCategory.hasMany(models.style,{
        as:'expensecategories'
    });
}

so the model in full will follow this structure and the other models as well

const ExpenseCategory = sequelize.define('ExpenseCategory', {
    id: {
        allowNull: false,
        autoIncrement: true,
        primaryKey: true,
        type: DataTypes.INTEGER
    },
    category: {
        allowNull: false,
        type: DataTypes.STRING
    }
});
ExpenseCategory.associate = (models) => {
    ExpenseCategory.hasMany(models.style,{
        as:'expensecategories'
    });
}
return ExpenseCategory;

This is with reference to this youtube video https://www.youtube.com/watch?v=SaVxJrTRkrI and this example from github for sequelize examples on associations for models https://github.com/sequelize/express-example/tree/master/models