下面給大家演示一個Rails中使用Find方法更加優雅的方式。例子中Task類有一個屬性complete表明任務是否已經完成(complete字段是false意味着未完成),incomplete和last_incomplete方法分別返回所有未完成的和最後一個未完成的任務。
class TaskController < ApplicationController
def incomplete
@tasks = Task.find(:all, :conditions => ['complete = ?', false])
end
def last_incomplete
@task = Task.find(:first, :conditions => ['complete =?', false], :order => 'created_at DESC')
end
end
查找所有未完成的任務,可以將代碼中下面的代碼用find_by_all替換。
@tasks = Task.find(:all, :conditions => ['complete = ?', false])
其中complete是條件字段的名字。
@tasks = Task.find_all_by_complete(false)
如果想查找某一個Task,使用find_by。如查找最後一個未完成的任務。
@task = Task.find(:first, :conditions => ['complete =?', false], :order => 'created_at DESC')
可以改爲
@task = Task.find_by_complete(false, :order => 'created_at DESC')
find_by方法可以像find方法樣接受order參數。
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原文鏈接:http://railscasts.com/episodes/2-dynamic-find-by-methods