我有一个Rails 3.1应用程序,我使用DataMapper作为ORM。当Rails应用程序作为控制台和服务器运行时,DataMapper的行为不同
我有以下型号(剥离):
class Task
include DataMapper::Resource
belongs_to :group
def project
group && group.project
end
end
class Group
include DataMapper::Resource
belongs_to :project
has n, :tasks
end
class Project
include DataMapper::Resource
has n, :groups
end
我发现,以不同的方式DataMapper的retreives数据时调用Task#project
当应用程序运行的服务器和控制台。
当作为服务器运行它试图获取一个组记录,结果是这样的(见PROJECT_ID):
#<Group @id=4 @created_at=Fri, 19 Apr 2013 06:13:25 +0000 @updated_at=Fri, 19 Apr 2013 06:13:25 +0000 @name="In Progress" @weight=<not loaded> @sync_updated_at=<not loaded> @sync_created_at=<not loaded> @capacity=<not loaded> @project_id=nil>
当作为控制台运行,并通过Group.get(4)
手动retreived,结果是这样的(见PROJECT_ID ):
#<Group @id=4 @created_at=Fri, 19 Apr 2013 06:13:25 +0000 @updated_at=Fri, 19 Apr 2013 06:13:25 +0000 @name="In Progress" @weight=<not loaded> @sync_updated_at=<not loaded> @sync_created_at=<not loaded> @capacity=<not loaded> @project_id=1>
的方法没有猴子补丁:
1.9.1 :060 > Group.instance_method(:project).source_location
=> ["/var/www/app/shared/bundle/ruby/1.9.1/gems/dm-core-1.2.0/lib/dm-core/model/relationship.rb", 333]
1.9.1 :061 > Group.instance_method(:project_id).source_location
=> ["/var/www/app/shared/bundle/ruby/1.9.1/gems/dm-core-1.2.0/lib/dm-core/model/property.rb", 206]
1.9.1 :062 > Group.instance_method(:project_id=).source_location
=> ["/var/www/app/shared/bundle/ruby/1.9.1/gems/dm-core-1.2.0/lib/dm-core/model/property.rb", 235]
1.9.1 :063 > Group.instance_method(:project=).source_location
=> ["/var/www/app/shared/bundle/ruby/1.9.1/gems/dm-core-1.2.0/lib/dm-core/model/relationship.rb", 358]
两种情况下的环境都是相同的。
SQL查询是不是在这两种情况下相同,但两者问PROJECT_ID的值:
控制台:
~ SQL (0.038ms) SET sql_auto_is_null = 0
~ SQL (0.028ms) SET SESSION sql_mode = 'ANSI,NO_BACKSLASH_ESCAPES,NO_DIR_IN_CREATE,NO_ENGINE_SUBSTITUTION,NO_UNSIGNED_SUBTRACTION,TRADITIONAL'
~ SQL (0.033ms) SELECT `id`, `type`, `created_at`, `updated_at`, `name`, `project_id` FROM `groups` WHERE `id` = 3 LIMIT 1
服务器:
SELECT `id`, `created_at`, `updated_at`, `type`, `name`, `project_id` FROM `groups` WHERE `id` = 3 ORDER BY `id`
我已经找到了一种解决方法但不应该要求。如果我改变Task#project
定义:
def project
group && Task.get(group.project_id)
end
它成功retreives相关任务。
任何想法可以导致这种差异?
我已经更新的问题发表评论。 – mspanc