我已经实现了用户-组关系模型，其中一个用户可以是一个或多个组的成员和所有者，一个组可以有一个或多个所有者和一个或多个成员。
现在，问题是User.owned_groups即使用户拥有超过 1 个组，也只返回 1 个组。
我面临与User.member_groups,Group.owners和相同的问题Group.members。所有方法都只返回 1 条记录。
以下是数据库中的模型和值。
楷模： -
require 'rubygems'
require 'data_mapper'
require 'dm-types'
module Contacts
class User
include DataMapper::Resource
property :id, Serial, :key => true
property :username, String, :required => true, :unique => true
has n, :group_owners, :child_key => [:owned_group_id]
has n, :owned_groups, 'Group', :through => :group_owners
has n, :group_members, :child_key => [:member_group_id]
has n, :member_groups, 'Group', :through => :group_members
#------------------------------------------#
# args should be an array of hashes #
# Example: args = [{:id => 1},{:id => 2}] #
#------------------------------------------#
def self.get_users args
users = Array.new
args.each do |user|
all_users = User.all(user)
all_users.each do |u|
user_hash = u.attributes
user_hash[:owned_groups] = Array.new
u.owned_groups.each do |owned_group|
g = owned_group.attributes
user_hash[:owned_groups].push g
end
user_hash[:member_groups] = Array.new
u.member_groups.each do |member_group|
g = member_group.attributes
user_hash[:member_groups].push g
end
users.push user_hash
end
end
return users
end
end
class Group
include DataMapper::Resource
property :id, Serial, :key => true
property :name, String, :required => true, :unique => true
has n, :group_owners, :child_key => [:owner_id]
has n, :owners, 'User', :through => :group_owners
has n, :group_members, :child_key => [:member_id]
has n, :members, 'User', :through => :group_members
#------------------------------------------#
# args should be an array of hashes #
# Example: args = [{:id => 1},{:id => 2}] #
#------------------------------------------#
def self.get_groups args
groups = Array.new
args.each do |group|
all_groups = Group.all(group)
all_groups.each do |g|
group_hash = g.attributes
group_hash[:owners] = Array.new
g.owners.each do |owner|
u = owner.attributes
group_hash[:owners].push u
end
group_hash[:members] = Array.new
g.members.each do |member|
u = member.attributes
group_hash[:members].push u
end
groups.push group_hash
end
end
return groups
end
end
class GroupOwner
include DataMapper::Resource
property :id, Serial, :key => true
belongs_to :owner, 'User'
belongs_to :owned_group, 'Group'
end
class GroupMember
include DataMapper::Resource
property :id, Serial, :key => true
belongs_to :member, 'User'
belongs_to :member_group, 'Group'
end
end
MySQL：-
mysql> select * from contacts_users;
+----+-----------+
| id | username |
+----+-----------+
| 1 | testuser1 |
| 2 | testuser2 |
+----+-----------+
mysql> select * from contacts_groups;
+----+------------+
| id | name |
+----+------------+
| 1 | testgroup1 |
| 2 | testgroup2 |
+----+------------+
2 rows in set (0.00 sec)
mysql> select * from contacts_group_owners;
+----+----------+----------------+
| id | owner_id | owned_group_id |
+----+----------+----------------+
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 1 | 2 |
| 4 | 2 | 2 |
+----+----------+----------------+
4 rows in set (0.00 sec)
mysql> select * from contacts_group_members;
+----+-----------+-----------------+
| id | member_id | member_group_id |
+----+-----------+-----------------+
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 1 | 2 |
| 4 | 2 | 2 |
+----+-----------+-----------------+
4 rows in set (0.00 sec)
在调试模式下，这是生成的 MySQL 查询User.owned_groups：
SELECT
`contacts_groups`.`id`,
`contacts_groups`.`name`,
`contacts_groups`.`created_at`,
`contacts_groups`.`updated_at`
FROM `contacts_groups`
INNER JOIN `contacts_group_owners`
ON `contacts_groups`.`id` = `contacts_group_owners`.`owned_group_id`
INNER JOIN `contacts_users`
ON `contacts_group_owners`.`owned_group_id` = `contacts_users`.`id`
WHERE `contacts_group_owners`.`owned_group_id` = 1
GROUP BY
`contacts_groups`.`id`,
`contacts_groups`.`name`,
`contacts_groups`.`created_at`,
`contacts_groups`.`updated_at`
ORDER BY `contacts_groups`.`id
版本：
红宝石 - 2.0.0-p0
西纳特拉 - 1.3.4
数据映射器 - 1.2.0
我错过了一些微不足道的事情吗？
提前致谢。