Node js and Sequelize insert to database

Question

In my project I am using MySQL database and Sequelize Js, I have two models created:

Post code model:

module.exports = function(sequelize, Sequelize) {

var Post_code = sequelize.define('post_code', {

    id: {
        autoIncrement: true,
        primaryKey: true,
        type: Sequelize.INTEGER(11)
    },

    code: {
        type: Sequelize.STRING(16),
        allowNull: false,
        unique: true
    },

    city: {
        type: Sequelize.STRING(45),
        allowNull: false
    }
},{
    freezeTableName: true,
    underscored: true
});

Post_code.associate = function(models) {
    models.post_code.hasMany(models.building);
};

   return Post_code;
}

Building model:

module.exports = function(sequelize, Sequelize) {

var Building = sequelize.define('building', {

    id: {
        autoIncrement: true,
        primaryKey: true,
        allowNull: false,
        type: Sequelize.INTEGER(11)
    },

    name: {
        type: Sequelize.STRING(100),
        allowNull: false
    },

    number: {
        type: Sequelize.INTEGER(11),
        allowNull: false
    },

    address: {
        type: Sequelize.STRING(255),
        allowNull: false
    },

    latitude: {
        type: Sequelize.DECIMAL(9,6),
        allowNull: false
    },

    longitude: {
        type: Sequelize.DECIMAL(9,6),
        allowNull: false
    }
},{
    freezeTableName: true,
    underscored: true
});

Building.associate = function (models) {
    models.building.belongsTo(models.post_code, {
        foreignKey: {
            allowNull: false
        }
    });

    models.building.hasMany(models.flat);
};

    return Building;
};

They are in relation one to many, it follows that Post code has many Buildings:

I want to add new building to database, when POST request is send to this route:

"/post-codes/:post_code_id/buildings"

I have access to post_code_id but I don't know how to correctly associate post_code model with building.

I was trying to do something like this:

models.post_code.findById(req.params.post_code_id)
.then(function(postCode){
    postCode.setBuilding(
        models.building.create({
        }).then(function(building){});  
    );    
});

But without result. I would be grateful if someone could explain how to make inserts correctly.

shouldn't you just need add the Building adding the Post-codeId to the object , from the parameter that you receive? — Ellebkey
– Ellebkey, Commented Mar 9, 2018 at 22:44
@Ellebkey Yes, that's correct, but I am searching for some build-in methods of making associations inside Sequelize. Other thing is that, yes, I can add post_code_id directly to building that I am going to create, but if something will happens that this parameter will be 'id' of post_code that does not exist in database, I will got an error. I didn't find simple explanation, but there is 'include' option inside model.create that I can use to create association probably in more secure way. — Marcin
– Marcin, Commented Mar 9, 2018 at 22:52

Ellebkey · Accepted Answer · 2018-03-09 23:46:17Z

1

I haven't heard about the include option on create, but you can do something like this:

db.post_code.find({
  where: {
    id: req.params.post_code_id
  }
}).then(post_code => {
  if (!post_code) {
    return res.status(404).send({
      message: 'No post_code with that identifier has been found'
    });
  } else {
    //create here your building
  }
}).catch(err => {
  return res.jsonp(err)
});

I don't know if this is the best way to do it, but it verify first if the post_code exists.

answered Mar 9, 2018 at 23:46

Ellebkey

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3 Comments

Marcin Over a year ago

link doc Here is link to documentation about this option, maybe if you want you can take a look. Anyway thank you for your respond.

Ellebkey Over a year ago

that's how define a N:M relationship, on your case you only need a 1:N relation. The include is use it when you need to do a join. So you'll include de post_code when you use find on Building cause it belongsTo

Marcin Over a year ago

but if you will take a look for section 'Creating elements of a "HasMany" or "BelongsToMany' association", my case consider "BelongsToMany" because building belongs to many post_codes, and there they are presenting way to create/associate product with many tags, and next, they are setting tags:(key) as array of tags/objects

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