我有徽章(类似StackOverflow)。ActiveRecord/Rails中的多列外键/关联
其中一些可以附加到可加标签的东西(例如,在帖子上添加了> X的评论徽章附加到帖子)。几乎所有人都进入多个级别(例如> 20,> 100,> 200),并且每个徽章x徽章类型只能有一个级别(= badgeset_id
)。
为了更容易执行的一个级别,每个徽章的约束,我想badgings由两列的外键,指定他们的徽章 - badgeset_id
和level
- 而不是由主键(badge_id
),虽然徽章也有一个标准的主键。
在代码:
class Badge < ActiveRecord::Base
has_many :badgings, :dependent => :destroy
# integer: badgeset_id, level
validates_uniqueness_of :badgeset_id, :scope => :level
end
class Badging < ActiveRecord::Base
belongs_to :user
# integer: badgset_id, level instead of badge_id
#belongs_to :badge # <-- how to specify?
belongs_to :badgeable, :polymorphic => true
validates_uniqueness_of :badgeset_id, :scope => [:user_id, :badgeable_id]
validates_presence_of :badgeset_id, :level, :user_id
# instead of this:
def badge
Badge.first(:conditions => {:badgeset_id => self.badgeset_id, :level => self.level})
end
end
class User < ActiveRecord::Base
has_many :badgings, :dependent => :destroy do
def grant badgeset, level, badgeable = nil
b = Badging.first(:conditions => {:user_id => proxy_owner.id, :badgeset_id => badgeset,
:badgeable_id => badgeable.try(:id), :badgeable_type => badgeable.try(:class)}) ||
Badging.new(:user => proxy_owner, :badgeset_id => badgeset, :badgeable => badgeable)
b.level = level
b.save
end
end
has_many :badges, :through => :badgings
# ....
end
如何我可以指定一个belongs_to
协会,这是否(以及不尝试使用badge_id
),这样我就可以使用has_many :through
?
ETA:这部分工作(即@ badging.badge作品),但感觉脏:
belongs_to :badge, :foreign_key => :badgeset_id, :primary_key => :badgeset_id, :conditions => 'badges.level = #{level}'
注意,条件是单引号,而不是增加一倍,这使得它在运行时进行解释,而比装载时间。
但是,当试图通过:through关联使用此功能时,出现错误undefined local variable or method 'level' for #<User:0x3ab35a8>
。并没有什么明显的(例如'badges.level = #{badgings.level}'
)似乎工作...
ETA 2:以EmFi的代码和清理它有点作品。它需要添加badge_set_id
徽章,这是多余的,但哦。
代码:
class Badge < ActiveRecord::Base
has_many :badgings
belongs_to :badge_set
has_friendly_id :name
validates_uniqueness_of :badge_set_id, :scope => :level
default_scope :order => 'badge_set_id, level DESC'
named_scope :with_level, lambda {|level| { :conditions => {:level => level}, :limit => 1 } }
def self.by_ids badge_set_id, level
first :conditions => {:badge_set_id => badge_set_id, :level => level}
end
def next_level
Badge.first :conditions => {:badge_set_id => badge_set_id, :level => level + 1}
end
end
class Badging < ActiveRecord::Base
belongs_to :user
belongs_to :badge
belongs_to :badge_set
belongs_to :badgeable, :polymorphic => true
validates_uniqueness_of :badge_set_id, :scope => [:user_id, :badgeable_id]
validates_presence_of :badge_set_id, :badge_id, :user_id
named_scope :with_badge_set, lambda {|badge_set|
{:conditions => {:badge_set_id => badge_set} }
}
def level_up level = nil
self.badge = level ? badge_set.badges.with_level(level).first : badge.next_level
end
def level_up! level = nil
level_up level
save
end
end
class User < ActiveRecord::Base
has_many :badgings, :dependent => :destroy do
def grant! badgeset_id, level, badgeable = nil
b = self.with_badge_set(badgeset_id).first ||
Badging.new(
:badge_set_id => badgeset_id,
:badge => Badge.by_ids(badgeset_id, level),
:badgeable => badgeable,
:user => proxy_owner
)
b.level_up(level) unless b.new_record?
b.save
end
def ungrant! badgeset_id, badgeable = nil
Badging.destroy_all({:user_id => proxy_owner.id, :badge_set_id => badgeset_id,
:badgeable_id => badgeable.try(:id), :badgeable_type => badgeable.try(:class)})
end
end
has_many :badges, :through => :badgings
end
虽然这个工作 - 这可能是一个更好的解决方案 - 我不认为这是一个实际的回答如何做)多键的外键的问题,或b)通过关联工作的动态条件关联。所以如果有人有解决方案,请说出来。
这或多或少有用。这不是问题的答案,尽管它是问题的答案,我也是这样认为的。 我已经清理了你的代码并把它放在了问题中。 – Sai 2009-10-28 00:10:46
我知道。你所问的似乎超出了Rails轻松完成的事情。你有没有找过插件?乍看之下,http://compositekeys.rubyforge.org/似乎可以做你想要的。 – EmFi 2009-10-28 00:51:02