まず定義の仕方としては 配列名.each do |変数|
処理
end
このように定義します。
このとき変数名はなんでも構いません。
言い方を変えるとこの処理は、配列内の０番目の要素を取り出し変数にその要素が代入され処理をする。次に1番目の要素を...
この作業を配列内に要素がなくなるまで繰り返すと言ったほうがわかりやすいかもしれません。
ActiveRecord::StatementInvalid in StudentsController#show
PG::UndefinedObject: ERROR: type "unsigned" does not exist LINE 1: ...id as subject_id, CAST(AVG(exam_results.score) as unsigned) ... ^ : SELECT subjects.id as subject_id, CAST(AVG(exam_results.score) as unsigned) as avg_score, MAX(exam_results.score) as max_score, MIN(exam_results.score) as min_score FROM "students" INNER JOIN "exam_results" ON "exam_results"."student_id" = "students"."id" INNER JOIN "subjects" ON "subjects"."id" = "exam_results"."subject_id" GROUP BY subjects.id ORDER BY subjects.id
def show
@students = Student.joins(:subjects)
.select('students.name, students.email, students.age, students.gender, students.opinion, subjects.id as subject_id')
.select('exam_results.name as exam_result_name, subjects.name as subject_name, exam_results.score')
.select('CAST((exam_results.score / subjects.max_score) * 100 as unsigned) as ratio')
.where(id: params[:id])
avg_result = Student.joins(:subjects)
.select('subjects.id as subject_id')
.select('CAST(AVG(exam_results.score) as unsigned) as avg_score')
.select('MAX(exam_results.score) as max_score')
.select('MIN(exam_results.score) as min_score')
.group('subjects.id')
.order('subjects.id')
(以下略)
# (該当部分だけ抜き出し）.select('CAST((exam_results.score / subjects.max_score) * 100 as int) as ratio').select('CAST(AVG(exam_results.score) as int) as avg_score')
ActiveRecord::StatementInvalid in StudentsController#show
PG::UndefinedObject: ERROR: type "unsigned" does not exist LINE 1: ...id as subject_id, CAST(AVG(exam_results.score) as unsigned) ... ^ : SELECT subjects.id as subject_id, CAST(AVG(exam_results.score) as unsigned) as avg_score, MAX(exam_results.score) as max_score, MIN(exam_results.score) as min_score FROM "students" INNER JOIN "exam_results" ON "exam_results"."student_id" = "students"."id" INNER JOIN "subjects" ON "subjects"."id" = "exam_results"."subject_id" GROUP BY subjects.id ORDER BY subjects.id
def show
@students = Student.joins(:subjects)
.select('students.name, students.email, students.age, students.gender, students.opinion, subjects.id as subject_id')
.select('exam_results.name as exam_result_name, subjects.name as subject_name, exam_results.score')
.select('CAST((exam_results.score / subjects.max_score) * 100 as unsigned) as ratio')
.where(id: params[:id])
avg_result = Student.joins(:subjects)
.select('subjects.id as subject_id')
.select('CAST(AVG(exam_results.score) as unsigned) as avg_score')
.select('MAX(exam_results.score) as max_score')
.select('MIN(exam_results.score) as min_score')
.group('subjects.id')
.order('subjects.id')
(以下略)
# (該当部分だけ抜き出し）.select('CAST((exam_results.score / subjects.max_score) * 100 as int) as ratio').select('CAST(AVG(exam_results.score) as int) as avg_score')
Rails.application.routes.draw do
get 'users/index'
get 'users/new'
get 'users/show'
get 'users/create'
get 'users/edit'
get 'users/update'
get 'users/destroy'
end
この状態でrails routesを実行すると。
$ rails routes
Prefix Verb URI Pattern Controller#Action
users_index GET /users/index(.:format) users#index
users_new GET /users/new(.:format) users#new
users_show GET /users/show(.:format) users#show
users_create GET /users/create(.:format) users#create
users_edit GET /users/edit(.:format) users#edit
users_update GET /users/update(.:format) users#update
users_destroy GET /users/destroy(.:format) users#destroy
Rails.application.routes.drawdo# get 'users/index'# get 'users/new'# get 'users/show'# get 'users/create'# get 'users/edit'# get 'users/update'# get 'users/destroy'resources:usersend
この状態でrails routes実行すると
$ rails routes
WARNING: Nokogiri was built against LibXML version 2.9.7, but has dynamically loaded 2.9.4
Prefix Verb URI Pattern Controller#Action
users GET /users(.:format) users#index
POST /users(.:format) users#create
new_user GET /users/new(.:format) users#new
edit_user GET /users/:id/edit(.:format) users#edit
user GET /users/:id(.:format) users#show
PATCH /users/:id(.:format) users#update
PUT /users/:id(.:format) users#update
DELETE /users/:id(.:format) users#destroy
$ rails routes
Prefix Verb URI Pattern Controller#Action
users_index GET /users/index(.:format) users#index
users_new GET /users/new(.:format) users#new
users_show GET /users/show(.:format) users#show
users_create GET /users/create(.:format) users#create
users_edit GET /users/edit(.:format) users#edit
users_update GET /users/update(.:format) users#update
users_destroy GET /users/destroy(.:format) users#destroy
Rails.application.routes.drawdo# get 'users/index'# get 'users/new'# get 'users/show'# get 'users/create'# get 'users/edit'# get 'users/update'# get 'users/destroy'resources:usersend
この状態でrails routes実行すると
$ rails routes
Prefix Verb URI Pattern Controller#Action
users GET /users(.:format) users#index
POST /users(.:format) users#create
new_user GET /users/new(.:format) users#new
edit_user GET /users/:id/edit(.:format) users#edit
user GET /users/:id(.:format) users#show
PATCH /users/:id(.:format) users#update
PUT /users/:id(.:format) users#update
DELETE /users/:id(.:format) users#destroy
