How do I add columns to an existing table in Rails migration?

How do I add columns to an existing table in Rails migration?

You can add columns to an existing table using the add_column method in a migration file. For example: add_column :table_name, :column_name, :data_type.

Can you show me a complete example of a migration file?

Sure! Here's a complete example:

class AddColumnsToUsers < ActiveRecord::Migration[6.0]
  def change
    add_column :users, :age, :integer
    add_column :users, :bio, :text
  end
end

What if I want to remove a column later?

You can remove a column using the remove_column method. For example: remove_column :table_name, :column_name.

Is there a way to add multiple columns at once?

Yes, you can add multiple columns in a single migration by calling add_column multiple times or using change_table. For example:

change_table :users do |t|
  t.integer :age
  t.text :bio
end