how to delete migration in rails code example

Example 1: how to reset migrations rails

To rollback all migrations the best solution is:

rake db:migrate VERSION=0
This will rollback any migrations without losing data. Then, run all migrations again with

rake db:migrate

Example 2: rails migration remove column

rails g migration Remove..From.. col1:type col2:type col3:type

#Exemple :

rails g migration RemoveCountryFromSampleApps country:string

Example 3: rails migration remove colum

remove_column :table_name, :column_name