Rails

创建scaffolding

generate scaffolding

rails generate scaffold your_scaffold_name
rails g scaffold your_scaffold_name # for short

删除scaffolding

destroy scaffolding

rails destroy scaffold your_scaffold_name

创建migration

generate migration

rails generate migration your_migration_name
rails g migration your_migration_name # for short
# example
rails g migration add_group_id_to_users
rails g migration create_groups name:string level:integer # with fields

Migration回滚

Migration rollback

rake db:rollback # rollback step 1
rake db:rollback STEP=n # rollback step n
rake db:migrate:down VERSION=version_number # rollback to version_number

创建或更新一条数据

Update or create a record in Active Record.

ModelName.find_or_initialize_by(feild1: feild1_of_find_by, feild2: feild2_of_find_by).update_attributes!(feild_need_update: feild_need_update_value)