Home how to check a record if it exists in another database
 ok so I am using devise and I created devise user, In a new migrate I added two cloumns to the users table as follows:  add_column :users, :userNum, :integer add_column :users, :isAdmin, :boolean, :default => false  and I created a new model called checkUser which created a migration which has a table as shown here: class CreateCheckUsers < ActiveRecord::Migration def change create_table :check_users do |t| t.integer :userNum t.boolean :isAdmin, :default => false t.timestamps null: false end end end  Then I inserted a record into the checkUser using the following command from the console: CheckUser.create(userNum:525252)  Now I want to check when the user enters the userNumber into the form. The checking should be as follows: If userNumber entered by user is already in checkUser table then set the field isAdmin in the users table to true, otherwise set it to false. edit: as I can see that my question is not so clear. So this is what I am trying to do. the project should have two type of users student and teacher ( admin ). So the CheckUser will have the userNum for all the teachers. and in the registration, when the user inputs their userNum then the program should check all the records in the CheckUser to see if the user is a teacher ( admin ) or not. What should I do next ? Thanks for your time