How to organize a node app that uses sequelize?

Question

I am looking for an example nodejs app that uses the sequelize ORM.

My main concern is that it seems next to impossible to define your models in separate js files if

Answer 1

I set it up as Farm and the documentation describe.

But I was having the additonal problem that in my instance methods and class methods that I would attach to the models in each function I would need to require the index file to get a hold of other database objects.

Solved it by making them accessible to all models.

var Config = require('../config/config');

 var fs = require('fs');
var path = require('path');
var Sequelize = require('sequelize');
var _ = require('lodash');
var sequelize;
var db = {};

var dbName, dbUsername, dbPassword, dbPort, dbHost;
// set above vars

var sequelize = new Sequelize(dbName, dbUsername, dbPassword, {
dialect: 'postgres', protocol: 'postgres', port: dbPort, logging: false, host: dbHost,
  define: {
    classMethods: {
        db: function () {
                    return db;
        },
        Sequelize: function () {
                    return Sequelize;
        }

    }
  }
});


fs.readdirSync(__dirname).filter(function(file) {
   return (file.indexOf('.') !== 0) && (file !== 'index.js');
}).forEach(function(file) {
  var model = sequelize.import(path.join(__dirname, file));
  db[model.name] = model;
});

Object.keys(db).forEach(function(modelName) {
  if ('associate' in db[modelName]) {
      db[modelName].associate(db);
  }
});

module.exports = _.extend({
  sequelize: sequelize,
  Sequelize: Sequelize
}, db);

And in the model file

var classMethods = {
  createFromParams: function (userParams) {
    var user = this.build(userParams);

    return this.db().PromoCode.find({where: {name: user.promoCode}}).then(function (code) {
        user.credits += code.credits;
                return user.save();
    });
  }

};

module.exports = function(sequelize, DataTypes) {
  return sequelize.define("User", {
  userId: DataTypes.STRING,
}, {  tableName: 'users',
    classMethods: classMethods
 });
};

I only did this for the class methods but you could also do the same thing for instance methods.

Answer 2

I am looking for an example nodejs app that uses the sequelize ORM.

You might be interested in looking at the PEAN.JS boilerplate solution.

• https://github.com/StetSolutions/pean

PEAN.JS is a full-stack JavaScript open-source solution, which provides a solid starting point for PostgreSQL, Node.js, Express, and AngularJS based applications.

The PEAN project is a fork of the MEAN.JS project (not to be confused with MEAN.IO or the generic MEAN stack).

• https://github.com/meanjs/mean

PEAN replaces MongoDB and the Mongoose ORM with PostgreSQL and Sequelize. A primary benefit of the MEAN.JS project is the organization it provides to a stack that has many moving pieces.

Answer 3

You can import models from other files with sequelize.import http://sequelizejs.com/documentation#models-import

That way you can have one singleton module for sequelize, which then loads all the other models.

Actually this answer is quite similar to user1778770`s answer.

Answer 4

SequelizeJS has a article on their website which solves this problem.

Link is broken, but you can find the working sample project here and browse it. See edited answer above to see why this is a better solution.

Extract from article:

• models/index.js

  The idea of this file is to configure a connection to the database and to collect all Model definitions. Once everything is in place, we will call the method associated on each of the Models. This method can be used to associate the Model with others.

        var fs        = require('fs')
          , path      = require('path')
          , Sequelize = require('sequelize')
          , lodash    = require('lodash')
          , sequelize = new Sequelize('sequelize_test', 'root', null)
          , db        = {} 
  
        fs.readdirSync(__dirname)
          .filter(function(file) {
            return (file.indexOf('.') !== 0) && (file !== 'index.js')
          })
          .forEach(function(file) {
            var model = sequelize.import(path.join(__dirname, file))
            db[model.name] = model
          })
  
        Object.keys(db).forEach(function(modelName) {
          if (db[modelName].options.hasOwnProperty('associate')) {
            db[modelName].options.associate(db)
          }
        })
  
        module.exports = lodash.extend({
          sequelize: sequelize,
          Sequelize: Sequelize
        }, db)
  

Answer 5

Sample model sequelize

'use strict';
const getRole   = require('../helpers/getRole')
const library   = require('../helpers/library')
const Op        = require('sequelize').Op

module.exports = (sequelize, DataTypes) => {
  var User = sequelize.define('User', {
    AdminId: DataTypes.INTEGER,
    name: {
      type: DataTypes.STRING,
      validate: {
        notEmpty: {
          args: true,
          msg: 'Name must be filled !!'
        },
      }
    },
    email: {
      type: DataTypes.STRING,
      validate: {
        notEmpty: {
          args: true,
          msg: 'Email must be filled !!'
        },
        isUnique: function(value, next) {
          User.findAll({
            where:{
              email: value,
              id: { [Op.ne]: this.id, }
            }
          })
          .then(function(user) {
            if (user.length == 0) {
              next()
            } else {
              next('Email already used !!')
            }
          })
          .catch(function(err) {
            next(err)
          })
        }
      }
    },
    password: {
      type: DataTypes.STRING,
      validate: {
        notEmpty: {
          args: true,
          msg: 'Password must be filled !!'
        },
        len: {
          args: [6, 255],
          msg: 'Password at least 6 characters !!'
        }
      }
    },
    role: {
      type: DataTypes.INTEGER,
      validate: {
        customValidation: function(value, next) {
          if (value == '') {
            next('Please choose a role !!')
          } else {
            next()
          }
        }
      }
    },
    gender: {
      type: DataTypes.INTEGER,
      validate: {
        notEmpty: {
          args: true,
          msg: 'Gender must be filled !!'
        },
      }
    },
    handphone: {
      type: DataTypes.STRING,
      validate: {
        notEmpty: {
          args: true,
          msg: 'Mobile no. must be filled !!'
        },
      }
    },
    address: DataTypes.TEXT,
    photo: DataTypes.STRING,
    reset_token: DataTypes.STRING,
    reset_expired: DataTypes.DATE,
    status: DataTypes.INTEGER
  }, {
    hooks: {
      beforeCreate: (user, options) => {
        user.password = library.encrypt(user.password)
      },
      beforeUpdate: (user, options) => {
        user.password = library.encrypt(user.password)
      }
    }
  });

  User.prototype.check_password = function (userPassword, callback) {
    if (library.comparePassword(userPassword, this.password)) {
      callback(true)
    }else{
      callback(false)
    }
  }

  User.prototype.getRole = function() {
    return getRole(this.role)
  }

  User.associate = function(models) {
    User.hasMany(models.Request)
  }

  return User;
};

---

Answer 6

I started using Sequelize in Express.js app. Soon enough ran into issues of the nature you're describing. Maybe I did not quite understand Sequelize, but to me doing things more than just selecting from one table wasn't really convenient. And where ordinarily you would use select from two or more tables, or a union in pure SQL, you would have to run separate queries, and with the async nature of Node it's just added complexity.

Therefore I moved away from using Sequelize. Moreover I am switching from using ANY data fetching from DB in the models. In my opinion it is better to abstract getting data completely. And reasons are - imagine that you don't just use MySQL (in my case, I use MySQL and MongoDB side by side), but you can get your data from any data provider and any transport method, e.g. SQL, no-SQL, filesystem, external API, FTP, SSH etc. If you tried to do all of it in the models, you would eventually create complex and hard to understand code that would be hard to upgrade and debug.

Now what you want to do is to have models get data from a layer that knows where and how to get it, but your models only use API methods, e.g. fetch, save, delete etc. And inside this layer you have specific implementations for specific data providers. E.g. you can request certain data from a PHP file on a local machine or from Facebook API or from Amazon AWS or from remote HTML document, etc.

PS some of these ideas were borrowed from Architect by Cloud9: http://events.yandex.ru/talks/300/