Question

我有一个关系模型，如果我编写自己的SQL，最好描述一下。为了简化，我写了这样的东西（在MyModel.rb中）：

has_many :platform_spots, :finder_sql => "SELECT * FROM platform_spots WHERE id=#{id}"

在模型描述中。

如果我现在运行rails console，并尝试拉

MyModel.find(:first)

我得到了

NameError: undefined local variable or method `id' for #<Class:0x000001039e4b80>

我认为它是因为我需要使用单引号，因此我将其更改为

has_many :platform_spots, :finder_sql => 'SELECT * FROM platform_spots WHERE id=#{id}'

现在，在控制台中

ecs = MyModel.find(:first)
ecs.platform_spots

我收到了错误

  PlatformSpot Load (0.2ms)  SELECT * FROM platform_spots WHERE id=#{id}
Mysql::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1: SELECT * FROM platform_spots WHERE id=#{id}
ActiveRecord::StatementInvalid: Mysql::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1: SELECT * FROM platform_spots WHERE id=#{id}

Answer 1

显然，您需要导轨3.1中的proc，如github问题中所述：https://github.com/rails/rails/issues/415以及https://stackoverflow.com/a/10620468/429850和https://stackoverflow.com/a/5465800/429850

中的其他SO答案

Answer 2

尝试重写它：

has_many :platform_spots, :class_name => "PlatformSpot",
            :finder_sql => proc {"select * from platform_spots where id = #{id}"}

行情：finder_sql

2 个答案: