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sheet 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Sheet.find(96).slots时：

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Slot.find_all_by_sheet_id(96)

编辑以上代码应该有效。虽然我使用Rails 4.1.8。也请尝试以下：

Slot.where(:sheet_id => 338)

Answer 2

find_by方法始终返回单个结果。

如果您想获得特定工作表的所有插槽，可以选择以下几种方法：

Sheet.find(96).slots或更有可能@sheet.slots如果您已找到该表

Slot.where(sheet_id: 96)也可以使用

要清楚，这与Rails控制台无关，而与.find_by方法有关。

Rails控制台设置限制为一个查询

2 个答案: