CREATE TABLE `t_user_history` (
`id` int(11) NOT NULL,
`history_no` int(11) NOT NULL,
`user_login_id` varchar(10) COLLATE utf8_unicode_ci NOT NULL,
`user_name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`user_pass` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`created_at` datetime DEFAULT NULL,
`updated_at` datetime DEFAULT NULL,
`deleted_at` datetime DEFAULT NULL,
`app_version` varchar(31) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`history_no`,`id`))

tuser = TUserHistory.find_by_id(user.id)
TUserHistory.transaction do
ntuser = TUserHistory.new
ntuser.id = tuser.id
ntuser.history_no = 0
ntuser.user_login_id = tuser.user_login_id
ntuser.user_name = tuser.user_name
ntuser.user_pass = tuser.user_pass
ntuser.app_version = params[:app]
ntuser.save

getName {"error_code":"Mysql2::Error: Column 'id' cannot be null: INSERT INTO `t_user_history`
(`app_version`, `created_at`, `deleted_at`, `history_no`, `id`, `updated_at`, `user_login_id`, `user_name`, `user_pass`)
VALUES ('v1.2.9', '2012-08-30 09:26:57', NULL, 0, NULL, '2012-08-30 09:26:57', 'userlogin', 'username', 'userpass')"}

class TUserHistory < ActiveRecord::Base
set_table_name "t_user_history"
default_scope select("id, user_login_id,user_name,user_pass,app_version")
acts_as_paranoid
end

tuser = TUserHistory.order("history_no DESC").find_by_id(user.id) #get last entry
    TUserHistory.transaction do
        id = tuser.id
        history_no = Integer(tuser.history_no)
        intHist_no = history_no + 1 #because this column doesn't auto-increment
        user_login_id = tuser.user_login_id
        user_name = tuser.user_name
        user_pass = tuser.user_pass
        app_version = params[:app]
        sql = "INSERT INTO t_user_history (id, history_no, user_login_id,user_name,user_pass,app_version) VALUES ('#{id}','#{intHist_no}','#{user_login_id}','#{user_name}','#{user_pass}','#{app_version}')"
         ActiveRecord::Base.connection.execute(sql)