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[英]How do you get Rails has_many through relations to work with has_many conditions?
[英]How do I shorten a triple Joins ActiveRecord Query with a has_many through relations?
我正在嘗試清理很長的ActiveRecord
查詢。 我的那個正在工作,盡管很難看。 這是正在發生的事情。
1) User
的has_many Simulations
通過UserSimulations
(反之亦然)。
2) User
的has_many Groups
通過UserGroups
(反之亦然)。
3)通過SimulationGroups
has_many Simulations
Group
(反之亦然)。
最終發生的事情是,可以通過兩種方式將用戶與Simulation
關聯,或者直接通過has_many到has_many關系,或者間接通過用戶所屬的Group
。
我已經能夠在一個查詢中收集用戶可以訪問的所有Simulations
,它看起來像這樣。 我可以訪問需要調用查詢的current_user
對象。
# Define Queries
user_sim_join = "LEFT JOIN user_simulations ON user_simulations.simulation_id = simulations.id"
user_grp_join = "LEFT JOIN user_groups ON user_groups.group_id = groups.id"
where_clause = ["user_groups.user_id = :user_id OR user_simulations.user_id = :user_id", { user_id: user.id }]
# Run Query
Simulation.joins(user_sim_join, :groups, user_grp_join).where(where_clause).group('simulations.id')
#=> Simulation Load (1.1ms) SELECT "simulations".* FROM "simulations"
INNER JOIN "simulation_groups" ON "simulation_groups"."simulation_id" = "simulations"."id"
INNER JOIN "groups" ON "groups"."id" = "simulation_groups"."group_id"
LEFT JOIN user_simulations ON user_simulations.simulation_id = simulations.id
LEFT JOIN user_groups ON user_groups.group_id = groups.id
WHERE (user_groups.user_id = 2 OR user_simulations.user_id = 2)
GROUP BY simulations.id
我很高興它能正常工作,但想對其進行簡化以使其更加簡潔(構建單個查詢的代碼不是4行)。
這是涉及的模型。
Simulation.rb
class Simulation < ApplicationRecord
# Associations
belongs_to :company
has_many :simulation_groups
has_many :user_simulations
has_many :objection_responses
has_many :groups, through: :simulation_groups
has_many :users, through: :user_simulations
has_many :reports, as: :reportable
has_many :objections, as: :objectionable
# Validations
end
Group.rb
class Group < ApplicationRecord
belongs_to :company
has_many :simulation_groups
has_many :simulations, through: :simulation_groups
has_many :user_groups
has_many :users, through: :user_groups
has_many :minigame_groups
has_many :minigames, through: :minigame_groups
has_many :reports, through: :users
# Validations
end
User.rb
class User < ApplicationRecord
# Associations
belongs_to :company
has_one :avatar
has_many :reports
has_many :events
has_many :training_sessions
has_many :user_groups
has_many :groups, through: :user_groups
has_many :objection_responses
has_many :user_simulations
has_many :simulations, through: :user_simulations
has_many :minigame_users
has_many :minigames, through: :minigame_users
# Validations
end
那這個呢?
scope :from_user, lambda{|user|
joins('left join user_simulations us ON (us.simulation_id = simulations.id)').
joins('left join group_simulations gs ON (gs.simulation_id = simulations.id)').
where("us.user_id = ? OR gs.group_id IN (?)",
user.id,
UserGroup.select("group_id").where(user_id: user.id))}
Simulation.from_user(user).to_sql:
"SELECT `simulations`.* FROM `simulations`
left join user_simulations us ON (us.simulation_id = simulations.id)
left join group_simulations gs ON (gs.simulation_id = simulations.id)
WHERE (us.user_id = 1 OR gs.group_id IN (
SELECT `user_groups`.`group_id` FROM `user_groups`
WHERE `user_groups`.`user_id` = 1))"
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