Rails 4 - 销毁HABTM记录导致未定义表

Question

我在事件和用户之间有一个has_and_belongs_to_many关系。

user.rb

class User < ActiveRecord::Base 
    rolify 
    has_and_belongs_to_many :events, join_table: :events_users 
    after_create :assign_default_role 

    devise :database_authenticatable, :registerable, 
     :recoverable, :rememberable, :trackable, :validatable 

    def assign_default_role 
    add_role(:basic) 
    end 
end 

event.rb

class Event < ActiveRecord::Base 
    rolify 
    has_and_belongs_to_many :users, join_table: :events_users 
end 

当我想删除的事件我做两件事情：

1. 删除所有关联（从events_users表）
2. 销毁事件（来自事件表）

所以我写了这个代码来实现这一目标：

events_controller.rb

def destroy 
    @event.users.clear #remove all associations 
    @event.destroy #destroy event 

    respond_to do |format| 
     flash[:success] = 'Event was successfully deleted.' 
     format.html { redirect_to events_url } 
     format.json { head :no_content } 
    end 
    end 

清算协会在连接表工作正常（@ event.users.clear）。

当它试图销毁实际的事件（@ event.destroy）时出现错误。

(0.7ms) BEGIN 
    SQL (0.4ms) DELETE FROM "events_users" WHERE "events_users"."event_id" = $1 [["event_id", 13]] 
PG::UndefinedTable: ERROR: relation "events_roles" does not exist 
LINE 5:    WHERE a.attrelid = '"events_roles"'::regclass 
             ^
:    SELECT a.attname, format_type(a.atttypid, a.atttypmod), 
        pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod 
       FROM pg_attribute a LEFT JOIN pg_attrdef d 
        ON a.attrelid = d.adrelid AND a.attnum = d.adnum 
       WHERE a.attrelid = '"events_roles"'::regclass 
       AND a.attnum > 0 AND NOT a.attisdropped 
       ORDER BY a.attnum 

    (0.3ms) ROLLBACK 
ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR: relation "events_roles" does not exist 
LINE 5:    WHERE a.attrelid = '"events_roles"'::regclass 
             ^
:    SELECT a.attname, format_type(a.atttypid, a.atttypmod), 
        pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod 
       FROM pg_attribute a LEFT JOIN pg_attrdef d 
        ON a.attrelid = d.adrelid AND a.attnum = d.adnum 
       WHERE a.attrelid = '"events_roles"'::regclass 
       AND a.attnum > 0 AND NOT a.attisdropped 
       ORDER BY a.attnum 

它似乎在寻找一个“events_ 角色”表，我不明白为什么。

（events_ 用户是有道理的，但events_ 角色是出于蓝）

帮助表示赞赏。

Answer 1

这将与您在Event类中的'rolify'相关。

class Event < ActiveRecord::Base 
    rolify 
    ... 

这是Rolify宝石，它可能会在数据库中生成额外的表/字段。