Rails 控制台设置限制为一个查询

Question

当我运行 ActiveRecord 查询时，Rails 控制台似乎将 LIMIT 1 附加到我的查询中。

所以我有一个 sheet，其中 has_many slots。当我查询 Slot.find_by(sheet_id: 96) 时，我得到：

Slot Load (2.3ms)  SELECT  "slots".* FROM "slots" WHERE "slots"."sheet_id" = ? LIMIT 1  [["sheet_id", 96]]
=> #<Slot id: 153, label: "Foo", name: "Foo", email: "", phone: "", comments: "Fighters", sheet_id: 96, created_at: "2015-04-30 14:28:47", updated_at: "2015-04-30 14:28:47">

但是当我查询时Sheet.find(96).slots:

Sheet Load (10.0ms)  SELECT  "sheets".* FROM "sheets" WHERE "sheets"."id" = ? LIMIT 1  [["id", 96]]
Slot Load (4.6ms)  SELECT "slots".* FROM "slots" WHERE "slots"."sheet_id" = ?  [["sheet_id", 96]]
=> #<ActiveRecord::Associations::CollectionProxy [#<Slot id: 153, label: "Foo", name: "Foo", email: "", phone: "", comments: "Fighters", sheet_id: 96, created_at: "2015-04-30 14:28:47", updated_at: "2015-04-30 14:28:47">, #<Slot id: 154, label: "Bar", name: "James", email: "", phone: "", comments: "Foobar", sheet_id: 96, created_at: "2015-04-30 14:28:47", updated_at: "2015-04-30 14:28:47">, ... >

Answer 1

你必须做Slot.find_all_by_sheet_id(96)

EDIT 上面的代码应该有效。虽然我用的是Rails4.1.8。也可以尝试以下操作：

Slot.where(:sheet_id => 338)

Answer 2

find_by 方法 returns 一个结果，总是。

如果您想获得特定 sheet 的所有插槽，有几个选项：

Sheet.find(96).slots 或更有可能 @sheet.slots 如果您已经找到 sheet

Slot.where(sheet_id: 96) 也可以

明确地说，这与 Rails 控制台无关，与 .find_by 方法有关。

Rails 控制台设置限制为一个查询

Rails console setting limit to one on queries

ruby-on-rails

rails-activerecord

rails-console

ruby-on-rails-4.2