Question

我有一个单表继承模型，如下所示：

class Application < ActiveRecord::Base
  has_many :snapshots, :dependent => :destroy
  has_many :foos, :dependent => :destroy
end

class Snapshot < ActiveRecord::Base
end

class Foo < Snapshot
end

Snapshot / Foo类的日期变量名称为'when' 当我添加：order =＆gt; 'when'（或：when）与has_many（foos）关系时，数据库在访问对象时抛出错误。例如application.foos.each ...

生成的查询：

SELECT "snapshots".* FROM "snapshots"  WHERE "snapshots"."type" IN ('Foo') AND "snapshots"."application_id" = 25 ORDER BY when

*错误接近“when”：语法错误

如果我手动编辑查询并将其输入rails dbconsole：

SELECT "snapshots".* FROM "snapshots"  WHERE "snapshots"."type" IN ('Foo') AND "snapshots"."application_id" = 25 ORDER BY "snapshots"."when"

查询有效。

这是一个已知的rails 3错误还是有一些特殊的语法？任何解决方法？

Answer 1

尝试计时

  query.order(:when)

Answer 2

试试这个

SELECT *FROM snapshots where type IN ('Foo') AND application_id = 25 ORDER BY when

Answer 3

尝试了许多有用之后：

@application.foos.order("\"snapshots\".\"when\"")

使用适当的“快照”生成查询。“when”

具有单表继承的关联Rails模型的ORDER BY错误

3 个答案: