Rails給關係表，SQLite3 :: SQLException帶來問題：沒有這樣的列

Question

似乎無法找到此解決方案。我有一個關係表，BlabsUser，我試圖找到並銷燬一條記錄。我這樣做：

BlabsUser.find_by_user_id_and_blab_id(1,29).destroy 

並獲得這個可愛的錯誤：

BlabsUser Load (0.2ms) SELECT "blabs_users".* FROM "blabs_users" WHERE "blabs_users"."user_id" = 1 AND "blabs_users"."blab_id" = 29 LIMIT 1 
Could not log "sql.active_record" event. NoMethodError: undefined method `name' for nil:NilClass 
SQLite3::SQLException: no such column: blabs_users.: DELETE FROM "blabs_users" WHERE "blabs_users"."" = ? 
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: blabs_users.: DELETE FROM "blabs_users" WHERE "blabs_users"."" = ? 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/sqlite3-1.3.5/lib/sqlite3/database.rb:91:in `initialize' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/sqlite3-1.3.5/lib/sqlite3/database.rb:91:in `new' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/sqlite3-1.3.5/lib/sqlite3/database.rb:91:in `prepare' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/sqlite_adapter.rb:234:in `block in exec_query' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:244:in `block in log' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/notifications/instrumenter.rb:21:in `instrument' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:239:in `log' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/sqlite_adapter.rb:223:in `exec_query' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/sqlite_adapter.rb:249:in `exec_delete' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/database_statements.rb:101:in `delete' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/query_cache.rb:14:in `delete' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/relation.rb:351:in `delete_all' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/persistence.rb:94:in `destroy' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/locking/optimistic.rb:119:in `destroy' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/callbacks.rb:254:in `block in destroy' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:390:in `_run_destroy_callbacks' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:81:in `run_callbacks' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/callbacks.rb:254:in `destroy' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/transactions.rb:236:in `block in destroy' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/transactions.rb:208:in `transaction' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/transactions.rb:293:in `with_transaction_returning_status' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.3/lib/active_record/transactions.rb:236:in `destroy' 
    from (irb):1 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands/console.rb:45:in `start' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands/console.rb:8:in `start' 
    from /Users/dylandrop/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.3/lib/rails/commands.rb:40:in `<top (required)>' 
    from script/rails:6:in `require' 
    from script/rails:6:in `<main>' 

爲什麼找一個叫blabs_users列？爲什麼它不只是在我的blabs_users表中尋找記錄？另外，更重要的是，我該如何解決這個問題？

編輯： 而且我也試過這個同樣的問題：

BlabsUser.destroy_all(:blab_id => 29, :user_id => 1) 

編輯2，爲每個請求： 我的模型只是

class BlabsUser < ActiveRecord::Base 
end 

遷移只是

class BlabsUsers < ActiveRecord::Migration 
    def self.up 
     create_table :blabs_users, :id => false, :force => true do |t| 
      t.integer :user_id 
      t.integer :blab_id 
      t.timestamps 
     end 
    end 

    def self.down 
     drop_table :blabs_users 
    end 
end 

Answer 1

ActiveRecord很大程度上依賴於使用一個唯一的鍵（通常是表的主鍵）由於您明確沒有定義（:id => false），我強烈懷疑您的問題與此有關。

destroy()也記錄爲銷燬具有給定ID的對象（或多個對象），這強烈建議它需要該唯一ID來處理。