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How to Add New Fields to Existing Sequelize Migration

nedsoft profile image Chinedu Orie ・1 min read

Sometimes you realize that you need to add some new fields to an existing sequelize migrations. This is especially important for production apps where refreshing the migration is not an option. Below is a quick guide on how to implement it.

Let's assume you want to add some new fields to Users table; below are the steps.

Step 1 - Create a new migration

npx sequelize-cli migration:create --name modify_users_add_new_fields
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Step 2 - Edit the migrations to suit the need

module.exports = {
  up(queryInterface, Sequelize) {
    return Promise.all([
      queryInterface.addColumn(
        'Users', // table name
        'twitter', // new field name
        {
          type: Sequelize.STRING,
          allowNull: true,
        },
      ),
      queryInterface.addColumn(
        'Users',
        'linkedin',
        {
          type: Sequelize.STRING,
          allowNull: true,
        },
      ),
      queryInterface.addColumn(
        'Users',
        'bio',
        {
          type: Sequelize.TEXT,
          allowNull: true,
        },
      ),
    ]);
  },

  down(queryInterface, Sequelize) {
    // logic for reverting the changes
    return Promise.all([
      queryInterface.removeColumn('Users', 'linkedin'),
      queryInterface.removeColumn('Users', 'twitter'),
      queryInterface.removeColumn('Users', 'bio'),
    ]);
  },
};
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Step 3 - Update the model with the new fields

Step 4 - Run migration

npx sequelize-cli db:migrate

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That is it, you have successfully added new fields to an existing migration.

Discussion (4)

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germantellezv profile image
Germán Téllez Vanegas

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

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ebzeal profile image
Olusola Ajayi

"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"

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rdecker573 profile image
rdecker573

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

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msamgan profile image
Mohammed Samgan Khan

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