rails g migration remove default

To remove a default value from a column in a Ruby on Rails migration using the rails g migration command, follow these steps:

1. Open your terminal or command prompt.
2. Navigate to your Rails application's root directory.
3. Run the following command: rails g migration remove_default. Replace remove_default with a descriptive name for your migration.
4. This command will generate a new migration file in the db/migrate directory.
5. Open the generated migration file. It will be named something like timestamp_remove_default.rb, where timestamp represents the date and time the migration was created.
6. Inside the migration file, you will see an empty change method.
7. Within the change method, use the change_column_default method to remove the default value from the desired column. The syntax for this method is as follows: change_column_default :table_name, :column_name, nil. Replace table_name with the name of the table containing the column, column_name with the name of the column itself, and nil to remove the default value.
8. Save the migration file.
9. Run the migration by executing the following command: rails db:migrate. This will apply the changes to your database schema.
10. Verify that the default value has been successfully removed from the column.

That's it! The default value for the specified column should now be removed. Remember to adjust the table_name and column_name values in the migration file to match your specific needs.