Rails的寻找方法 - 选择列从＆QUOT;：包括＆QUOT;表参数 [英] Rails find method - select columns from ":include" table parameter

问题描述

下面find方法将返回所有记录，但不包括场地表列。有没有一种方法，我可以修改下面包括场馆列？我试过：选择=＆GT; venues.id和：选择=＆GT; 场地。*，都无济于事。也许这是一个限制与轨道寻找方法。可查询被改写为可能Item.where包括所有列？

The below find method returns all records but doesn't include venues table columns. Is there a way I can modify the below to include columns from venues? I tried :select => 'venues.id', and :select => 'venues.*', to no avail. Perhaps this is a limitation with the rails find method. Can the query be rewritten as perhaps "Item.where" to include all columns?

@vehicles = Vehicle.find(:all, 
      :select => '*',
      :joins => [:vehicle_status, :category, :user],
      :include => [:venue],
      :conditions => ["vehicles.client_id = ? ", current_user.client_id]
      )

我使用的是轨道3.2.11。

I'm using rails 3.2.11.

另外，我当我使用：选择=＆GT; '。*的车辆，场地*，并得到它显示了被选择的场地领域控制台上的后续查询，但它们不会出现在返回的JSON：

Also, my when I use :select => 'vehicles.*, venues.*' and get the follow query on the console where it shows venues fields being selected, but they do not appear in the returned json:

    SELECT "vehicles"."id" AS t0_r0, ... "vehicles"."created_at" AS t0_r33, 
"vehicles"."updated_at" AS t0_r34, "venues"."id" AS t1_r0, "venues"."client_id" AS t1_r1, 
"venues"."venue_name" AS t1_r2, "venues"."created_at" AS t1_r3, "venues"."updated_at" AS t1_r4 
FROM "vehicles" INNER JOIN "vehicle_statuses" ON "vehicle_statuses"."vehicle_status_code" = 
"vehicles"."status_code" INNER JOIN "categories" ON "categories"."id" = 
"vehicles"."category_id" INNER JOIN "users" ON "users"."id" = "vehicles"."created_at_user_id" 
LEFT OUTER JOIN "venues" ON "venues"."id" = "vehicles"."venue_id" WHERE (vehicles.client_id = 
500 )

不过，如果我使用：选择=＆GT; '*'，控制台显示两个查询：一个用于车辆表，另一个是场地：场地负载（0.3ms）选择场地* FROM场地WHERE场地。 ID在（5000）

However, if I use :select => '*', the console shows two queries: one for the vehicles table, the other for venue: Venue Load (0.3ms) SELECT "venues".* FROM "venues" WHERE "venues"."id" IN (5000)

推荐答案

您应该尝试

format.json { render json: @vehicles, :include => :venue }

您也可以做一个加入

@vehicles = Vehicle.where(client_id: current_user.client_id).joins(:category, :vehicle_status).includes(:venue) 

场地或根据的has_many 场地或 HAS_ONE 。欲了解更多信息查找的东西在这里 http://guides.rubyonrails.org/active_record_querying.html

venue or venues depending on has_many or has_one. For further information lookup stuff here http://guides.rubyonrails.org/active_record_querying.html

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