[英]has_many :through multiple joins table
I'm trying to create a 4 way joins table.我正在尝试创建一个 4 路连接表。
class User < ApplicationRecord
has_many :user_configurations
has_many :teams, through: :user_configurations
has_many :companies, through: :user_configurations
scope :supervisors, -> { joins(:user_configurations).where(user_configurations: { supervisor: true }) }
scope :agents, -> { joins(:user_configurations).where(user_configurations: { supervisor: false }) }
end
class Team < ApplicationRecord
has_many :user_configurations
has_many :users, through: :user_configurations
belongs_to :company_unit
end
class CompanyUnit < ApplicationRecord
has_many :user_configurations
has_many :users, through: :user_configurations
has_many :teams
belongs_to :company
end
class Company < ApplicationRecord
has_many :user_configurations
has_many :users, through: :user_configurations
has_many :company_units
has_many :teams, through: :company_units
end
class UserConfiguration < ApplicationRecord
belongs_to :user, optional: true
belongs_to :team, optional: true
belongs_to :company, optional: true
#supervisor:boolean in this table
end
When I create I get 2 separate entries into the UserConfiguration Table.当我创建时,我在 UserConfiguration 表中获得了 2 个单独的条目。
Company.first.users.create(team_ids: [1])
id: 1, user_id: 1, team_id: nil, company_id: 1
id: 2, user_id: 1, team_id: 1, company_id: nil
I don't know if it's good practice to attempt something like this any suggestions will be really helpful thanks.我不知道尝试这样的事情是否是一种好习惯,任何建议都会非常有帮助,谢谢。 Every search results in trying to do a sql join to query data.
每个搜索都会导致尝试执行 sql 连接来查询数据。
EDIT: Decided not to do this and will try and figure out a different approach.编辑:决定不这样做,并会尝试找出不同的方法。
I would set it up with indirect relationships instead:我会用间接关系来设置它:
class User
has_many :employments
has_many :companies, through: :employments
has_many :positions
has_many :teams, through: :positions
end
class Company
has_many :employments
has_many :users, through: :employments
has_many :teams, through: :users
end
class Team
has_many :positions
has_many :users, through: :positions
has_many :companies, through: :users
end
# join model between User and Company
class Employment
belongs_to :user
belongs_to :company
end
# join model between User and Team
class Position
belongs_to :user
belongs_to :team
end
While you could potentially use a single 3 way join model this violates the Single Responsibility Principle and does not map the domain very well.虽然您可能会使用单一的 3 路连接模型,但这违反了单一职责原则并且不能很好地映射域。
3 way joins introduce quite a bit of complexity as you cannot simply unlink two records by deleting a row in the join table. 3 路连接引入了相当多的复杂性,因为您不能通过删除连接表中的一行来简单地取消两条记录的链接。 And ActiveRecord does not automatically keep track of the foreign key columns.
并且 ActiveRecord 不会自动跟踪外键列。
If you want to add roles to this data model there are a few ways to do it:如果你想向这个数据模型添加角色,有几种方法可以做到:
# join model between User and Team
class Position
enum role: [:grunt, :supervisor]
belongs_to :user
belongs_to :team
end
class User
has_many :user_roles
has_many :roles, through: :user_roles
def has_role?(name, resource = nil)
roles.exists?(name: name, resource: resource)
end
end
class Role
belongs_to :resource, polymorpic: true, optional: true
has_many :user_roles
end
class UserRole
belongs_to :user
belongs_to :role
end
This is a really flexible system lets you attach roles to anything - companies, teams etc. And lets you build systems where the roles can even by defined by end users.这是一个非常灵活的系统,可以让您将角色附加到任何东西 - 公司、团队等。并且可以让您构建系统,其中角色甚至可以由最终用户定义。 Check out the rolify gem for a full example.
查看rolify gem以获取完整示例。
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