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How to Add New Fields to Existing Sequelize Migration

Chinedu Orie on February 28, 2020

Sometimes you realize that you need to add some new fields to an existing sequelize migrations. This is especially important for production apps wh...

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Germán Téllez Vanegas • Nov 4 '20

Hi, great tutorial. Does this keep the data in the database? or does it remove all data?

Olusola Ajayi • Nov 6 '20

"npx sequelize-cli db:migrate" keeps the data in the database. To wipe the database you'd need to do "npx sequelize-cli db:migrate:undo:all" before "npx sequelize-cli db:migrate"

rdecker573 • Feb 26 '21

If a migration is rolled back, I think that will remove data.

sammy kapienga • Oct 7 '21

Keeps data

Miracle Nwaubani • Jun 12 '23

@nedsoft please I want to ask how can one generate migration from existing model, say you have model in user.js file and you already defined your user model

`/* eslint-disable no-unused-vars */
'use strict';
const {  Model } = require('sequelize');
module.exports = (sequelize, DataTypes) => {
  class User extends Model {}

  User.init({
    first_name: {
      type: DataTypes.STRING,
      allowNull: false
    },
    last_name: {
      type: DataTypes.STRING,
      allowNull: false
    },
    password: {
      type: DataTypes.STRING,
      allowNull: false
    }
  }, 
  {
    sequelize,
    modelName: 'User',
    tableName: 'Users'
  });
  return User;
};`

how do I now generate migration base on this existing model?

Ankur Bansal • Sep 13 '23

Sequelize supports a feature called "model migrations," where you can generate and apply migrations directly from your Sequelize model definitions. This approach simplifies the process of making schema changes. You can use the npx sequelize migration:generate command with the --name option to create a migration based on changes in your models. For example:

npx sequelize migration:generate --name update-models

This command will generate a migration file with changes based on the differences between your models and the current database schema. You can then run the migration as usual.

Note that this approach requires you to have well-defined Sequelize models that accurately represent your database schema.

Saikat Banerjee • Nov 18 '21

How to maintain sequence of the coloumn to be added while creating the coloumn. if I need to add the coloumn after a particular coloumn which already exists. By the above implementation the coloumn will always be added at the end of the list.

Nicola Lauritano • May 7 '22

Hi all,

When I run npx sequelize-cli db:migrate I got this error:

Cannot find "{myPath}/config/config.json". Have you run "sequelize init"?

I don't have a config.json file, should I create it or maybe it should be created by npx sequelize-cli migration:create --name modify_users_add_new_fields ?

If I have to create, how it should be?

Thanks all guys

vladorjiggy • Sep 30 '22

This tutorial describes how to extend a existing migration. If you haven't used the CLI for your project, you have to initialize it by npx sequelize init

Mohamed Hamada • Jun 28 '21

Thanks very much !
there is no much tutorials for these things out there!

Mohammed Samgan Khan • Apr 26 '21

what fi i want to add the new field after a particular field.

Guryash Singh • Jan 3 '22

How can we add a column after specific column?

Mike Dodge • Feb 22 '22

Like this:
return Promise.all([ queryInterface.addColumn( 'users', // table name 'verifier', // new field name { type: Sequelize.STRING, allowNull: true, after: 'manager_bonus', } ), ]);