Rails的find_or_create_by有/无的地方 [英] Rails find_or_create_by with/without where

问题描述

让我们说我有一个名为模型工作。我想 find_or_create_by 一些任务。

Let's say I have a model named Task. And I want to find_or_create_by some task.

t = Task.where(done: false).find_or_create_by(title: 'epic')

这个样板工程，但是创建标题等于史诗完成等于假的任务。我想通过查询搜索做等于假的，但我不希望新的记录完成等于假。我该怎么办呢？

This model works, but create a task with title equal to epic and done equal to false. I want query search through done equal to false, but I don't want new record done equal to false. How can I do it?

推荐答案

您可以使用一种叫做：的 find_or_initialize_by 。它只是初始化记录，但不会创建它。通过这种方式，你可以替换的属性后面：

You can use something called: find_or_initialize_by. It only initializes the record, but doesn't create it. This way, you can override the properties later on:

 task = Task.where(done: false).find_or_initialize_by(title: 'epic').first
 task.done = true # or nil or whatever you want!
 task.save

我只保存 task.done = TRUE 第一条记录。如果有一个以上的记录，你可以使用每个来遍历所有这些，并保存它们。

I only saved the first record with task.done = true. If there are more than one record, you can use each to iterate through all of them, and save them all.

编辑：

Task.where(:done => false).first_or_initialize do |task|
  task.done = true
  task.title = 'epic'
end

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