ActiveRecordからカラムの型情報を得る

次のスクリプトで、テーブル定義とActiveRecordクラスを用意します。

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Schema.define do
   create_table :employees do |t|
     t.string :name
     t.integer :age
     t.boolean :admin
     t.date :hired_at
     t.decimal :salary
     t.float :loyalty
   end
end
class Employee < ActiveRecord::Base; end

Employee.columns_hash.map{[_1,_2.type]}.to_h
=>
{"id"=>:integer,
 "name"=>:string,
 "age"=>:integer,
 "admin"=>:boolean,
 "hired_at"=>:date,
 "salary"=>:decimal,
 "loyalty"=>:float}

参考

stackoverflow.com