How To Change the Column Name and Column Type

1.How to change a column name in a migration:

1. Generate a migration in the console: rails g migration ChangeColumnName
2. Go to the generated migration file and modify the change method in this way: rename_column :table_name, :old_column, :new_column
3. class ChangeColumnName < ActiveRecord::Migration[5.0]
4. def change
5. rename_column :users, :email, :email_address
6. end
7. end
8. Run rails db:migrate, and don’t forget to update your code with the new name                                                                                                                              NOTICE:
9. Be careful with the reserved names in Rails or SQL when you rename a columnSomething to look out when you rename a column in Rails: the reserved names. You will run into troubles if you use them, sometimes not right away.
10. And there are a LOT of them. Therefore, you can’t rename your database column using ‘group’, ‘image’, ‘set’, ‘open’, etc.                                                                        

    2.How to change a Column Type in a migration:

11. Generate a migration in the console: rails g migration ChangeColumnName
12. Go to the generated migration file and modify the change method in this way: rename_column :table_name, :table_name, :new_type
13. Run rails db:migrate, and don’t forget to update your code with the new name
14. class ChangeDateColumnToDatetime < ActiveRecord::Migration[5.0]
15. def up
16. change_column :projects, :deadline, :datetime
17. end
19. def down
20. change_column :projects, :deadline, :date
21. end
22. .