「Ruby/rails/db関連付け」の版間の差分
提供: 初心者エンジニアの簡易メモ
(→1:n) |
(→命名規則が使えない場合の1:n紐付け) |
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| (同じ利用者による、間の5版が非表示) | |||
| 行6: | 行6: | ||
has_one :through | has_one :through | ||
has_and_belongs_to_many | has_and_belongs_to_many | ||
| + | |||
| + | ==belongs_to関連付けオプション== | ||
| + | :autosave | ||
| + | :class_name | ||
| + | :counter_cache | ||
| + | :dependent | ||
| + | :foreign_key | ||
| + | :primary_key | ||
| + | :inverse_of | ||
| + | :polymorphic | ||
| + | :touch | ||
| + | :validate | ||
| + | :optional | ||
==1:n関連のデータ取得例== | ==1:n関連のデータ取得例== | ||
| 行19: | 行32: | ||
logger.debug("battle.user.name=#{battle.user.name}") | logger.debug("battle.user.name=#{battle.user.name}") | ||
end | end | ||
| + | |||
| + | ==1:1関連のデータ取得例== | ||
| + | class Supplier < ApplicationRecord | ||
| + | has_one :account | ||
| + | end | ||
| + | class Account < ApplicationRecord | ||
| + | end | ||
| + | |||
| + | acounts = Account.all | ||
| + | acounts.each do |account| | ||
| + | logger.debug("account.supplier.name=#{account.supplier.name}") | ||
| + | end | ||
| + | |||
| + | ==命名規則が使えない場合の1:n紐付け== | ||
| + | battles.battle_user_idをusers.idと紐づける | ||
| + | class User < ApplicationRecord | ||
| + | has_many :battle | ||
| + | end | ||
| + | class Battle < ApplicationRecord | ||
| + | belongs_to :user | ||
| + | belongs_to :battle_user, class_name: "User" | ||
| + | end | ||
| + | |||
| + | battles = Battle.where("user_id = ?", params[:id]) | ||
| + | battles.each do |battle| | ||
| + | logger.debug("battle.user_id=#{battle.battle_user.name}") | ||
| + | end | ||
| + | |||
| + | ==参考== | ||
| + | 公式rails関連付け：https://railsguides.jp/association_basics.html | ||
2017年11月17日 (金) 07:35時点における最新版
関連付け一覧
belongs_to has_one has_many has_many :through has_one :through has_and_belongs_to_many
belongs_to関連付けオプション
:autosave :class_name :counter_cache :dependent :foreign_key :primary_key :inverse_of :polymorphic :touch :validate :optional
1:n関連のデータ取得例
class Battle < ApplicationRecord belongs_to :user end class User < ApplicationRecord has_many :battle end
battles = Battle.where("user_id = ?", params[:id])
battles.each do |battle|
logger.debug("battle.user.name=#{battle.user.name}")
end
1:1関連のデータ取得例
class Supplier < ApplicationRecord has_one :account end class Account < ApplicationRecord end
acounts = Account.all
acounts.each do |account|
logger.debug("account.supplier.name=#{account.supplier.name}")
end
命名規則が使えない場合の1:n紐付け
battles.battle_user_idをusers.idと紐づける
class User < ApplicationRecord has_many :battle end class Battle < ApplicationRecord belongs_to :user belongs_to :battle_user, class_name: "User" end
battles = Battle.where("user_id = ?", params[:id])
battles.each do |battle|
logger.debug("battle.user_id=#{battle.battle_user.name}")
end
参考
公式rails関連付け：https://railsguides.jp/association_basics.html
