counter_cache沒有遞增...我做錯了什麼？

Question

這似乎超級簡單，所以正在讓我的生活悲慘。 Rails 3.1.3。

編輯：基於以下建議添加t.integer「versions_count」，：default => 0遷移，回滾，重新創建數據庫。現在versions_count停留在0

#version.rb:  
class Version < ActiveRecord::Base 
    belongs_to :document, :counter_cache => true 
end 

#document.rb 
class Document < ActiveRecord::Base 
    has_many :versions 
end 

#schema.rb: 
create_table "documents", :force => true do |t| 
    t.text  "name" 
    #EDIT: Added a default (see below) t.integer "versions_count" 
    t.integer "versions_count", :default => 0 
    t.datetime "created_at" 
    t.datetime "updated_at" 
end 

create_table "versions", :force => true do |t| 
    t.text  "name" 
    t.integer "document_id" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
end 

控制檯：

1.9.2-p290 :001 > d = Document.new 
=> #<Document id: nil, name: nil, versions_count: nil, created_at: nil, updated_at: nil> 
1.9.2-p290 :002 > d.name = "doc 1" 
=> "doc 1" 
1.9.2-p290 :003 > d.save 
    SQL (79.9ms) INSERT INTO "documents" ("created_at", "name", "updated_at", "versions_count") VALUES (?, ?, ?, ?) [["created_at", Sat, 04 Feb 2012 04:34:51 UTC +00:00], ["name", "doc 1"], ["updated_at", Sat, 04 Feb 2012 04:34:51 UTC +00:00], ["versions_count", nil]] 
=> true 
1.9.2-p290 :004 > v = Version.new 
=> #<Version id: nil, name: nil, document_id: nil, created_at: nil, updated_at: nil> 
1.9.2-p290 :005 > v.name = "v1" 
=> "v1" 
1.9.2-p290 :006 > v.save 
    SQL (1.0ms) INSERT INTO "versions" ("created_at", "document_id", "name", "updated_at") VALUES (?, ?, ?, ?) [["created_at", Sat, 04 Feb 2012 04:35:13 UTC +00:00], ["document_id", nil], ["name", "v1"], ["updated_at", Sat, 04 Feb 2012 04:35:13 UTC +00:00]] 
=> true 
1.9.2-p290 :007 > d 
=> #<Document id: 1, name: "doc 1", versions_count: nil, created_at: "2012-02-04 04:34:51", updated_at: "2012-02-04 04:34:51"> 
1.9.2-p290 :008 > d.versions << v 
    (0.3ms) UPDATE "versions" SET "document_id" = 1, "updated_at" = '2012-02-04 04:35:24.490334' WHERE "versions"."id" = 1 
    Version Load (0.2ms) SELECT "versions".* FROM "versions" WHERE "versions"."document_id" = 1 
=> [#<Version id: 1, name: "v1", document_id: 1, created_at: "2012-02-04 04:35:13", updated_at: "2012-02-04 04:35:24">] 
1.9.2-p290 :009 > d.save 
=> true 
1.9.2-p290 :010 > d.versions_count 
=> nil 
1.9.2-p290 :016 > v.save 
=> true 
1.9.2-p290 :017 > d 
=> #<Document id: 1, name: "doc 1", versions_count: nil, created_at: "2012-02-04 04:34:51", updated_at: "2012-02-04 04:34:51"> 
1.9.2-p290 :018 > d2 = Document.first 
    Document Load (0.3ms) SELECT "documents".* FROM "documents" LIMIT 1 
=> #<Document id: 1, name: "doc 1", versions_count: nil, created_at: "2012-02-04 04:34:51", updated_at: "2012-02-04 04:34:51"> 

請幫幫忙，我發瘋。

編輯2：似乎刪除關聯的記錄時計數器減去它的值。但它從來沒有得到補充。

1.9.2-p290 :200 > d = Document.first 
    Document Load (0.4ms) SELECT "documents".* FROM "documents" LIMIT 1 
=> #<Document id: 1, name: "doc 1", versions_count: 0, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:15:25"> 
1.9.2-p290 :201 > d.versions 
    Version Load (0.3ms) SELECT "versions".* FROM "versions" WHERE "versions"."document_id" = 1 
=> [] 
1.9.2-p290 :202 > v1 = Version.first 
    Version Load (0.3ms) SELECT "versions".* FROM "versions" LIMIT 1 
=> #<Version id: 1, name: "v1", document_id: nil, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:13:47"> 
1.9.2-p290 :203 > v2 = Version.last 
    Version Load (0.3ms) SELECT "versions".* FROM "versions" ORDER BY "versions"."id" DESC LIMIT 1 
=> #<Version id: 2, name: "v2", document_id: nil, created_at: "2012-02-04 21:59:12", updated_at: "2012-02-04 22:11:37"> 
1.9.2-p290 :204 > d.versions << v1 
    (1.5ms) UPDATE "versions" SET "document_id" = 1, "updated_at" = '2012-02-04 22:16:09.876354' WHERE "versions"."id" = 1 
=> [#<Version id: 1, name: "v1", document_id: 1, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:16:09">] 
1.9.2-p290 :205 > d.versions << v2 
    (0.6ms) UPDATE "versions" SET "document_id" = 1, "updated_at" = '2012-02-04 22:16:15.628396' WHERE "versions"."id" = 2 
=> [#<Version id: 1, name: "v1", document_id: 1, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:16:09">, #<Version id: 2, name: "v2", document_id: 1, created_at: "2012-02-04 21:59:12", updated_at: "2012-02-04 22:16:15">] 
1.9.2-p290 :206 > d.save 
=> true 
1.9.2-p290 :207 > d 
=> #<Document id: 1, name: "doc 1", versions_count: 0, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:15:25"> 
1.9.2-p290 :208 > d.versions 
=> [#<Version id: 1, name: "v1", document_id: 1, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:16:09">, #<Version id: 2, name: "v2", document_id: 1, created_at: "2012-02-04 21:59:12", updated_at: "2012-02-04 22:16:15">] 
1.9.2-p290 :209 > d.versions = [] 
    SQL (1.8ms) UPDATE "versions" SET "document_id" = NULL WHERE "versions"."document_id" = 1 
    SQL (0.2ms) UPDATE "documents" SET "versions_count" = COALESCE("versions_count", 0) - 2 WHERE "documents"."id" = 1 
=> [] 
1.9.2-p290 :210 > d 
=> #<Document id: 1, name: "doc 1", versions_count: -2, created_at: "2012-02-04 21:49:31", updated_at: "2012-02-04 22:15:25"> 
1.9.2-p290 :211 > 

Answer 1

我不認爲counter_cache從零工作。您需要使默認值0

add_column :documents, : versions_count, :integer, :default => 0