All models validation for SSN and TIN is working as intended except the Participant model. An error message won't display and the buttons grey out but it won't create as intended.

app/controllers/participants_controller.rb

@@ -33,15 +33,17 @@ class ParticipantsController < ApplicationController
       if @participant.save
         redirect_to @participant, notice: 'Participant was successfully created.'
       else
-        render :new
+        flash.now[:alert] = 'There was an error creating the participant.'
+        render :new, status: :unprocessable_entity
       end
     end
   rescue ActiveRecord::RecordInvalid => e
     flash.now[:alert] = "Error: #{e.message}"
-    render :new
+    render :new, status: :unprocessable_entity
   end
   
   
+  
   def edit
   end
 

app/models/employer.rb

@@ -16,6 +16,8 @@ class Employer < ApplicationRecord
 
   
   validate :unique_as_participant
+  validates :ssn, uniqueness: true, allow_blank: true, presence: true
+  validates :tin, uniqueness: true, allow_blank: true, presence: true
   
   private
   

app/models/participant.rb

@@ -7,15 +7,21 @@ class Participant < ApplicationRecord
   has_many :vendors, through: :service_contracts
   has_many :employer_records
   has_many :employers, through: :employer_records
-
+  has_and_belongs_to_many :programs
 
   # Validations
-  validates :first_name, presence: true
+  validates :first_name, :last_name, :ssn, presence: true
-  validates :last_name, presence: true
+  validate :ssn_must_be_unique_across_models
+
   def full_name
     "#{first_name} #{last_name}"
   end
 
-  # Other associations
+  private
-  has_and_belongs_to_many :programs
+
+  def ssn_must_be_unique_across_models
+    if Participant.where.not(id: id).exists?(ssn: ssn) || Employer.exists?(ssn: ssn)
+      errors.add(:ssn, 'SSN is already taken by another participant or employer')
+    end
+  end
 end

app/models/vendor.rb

@@ -3,4 +3,7 @@ class Vendor < ApplicationRecord
   has_and_belongs_to_many :employers
   has_many :service_contracts
   has_many :participants, through: :service_contracts
+
+  # Validations
+  validates :tin, uniqueness: true, allow_blank: true, presence: true
 end

app/models/worker.rb

@@ -12,6 +12,7 @@ class Worker < ApplicationRecord
   # Validations
   validates :first_name, presence: true
   validates :last_name, presence: true
+  validates :ssn, uniqueness: true, allow_blank: true, presence: true
 
   # Method to return the full name of the worker
   def full_name

app/views/participants/_form.html.erb

@@ -1,9 +1,9 @@
 <%= form_with(model: participant, local: true, html: { class: 'needs-validation', novalidate: true }) do |form| %>
-  <% if participant.errors.any? %>
+  <% if @participant.errors.any? %>
-    <div id="error_explanation" class="alert alert-danger" role="alert">
+  <div id="error_explanation" class="alert alert-danger">
-      <h4><%= pluralize(participant.errors.count, "error") %> prohibited this participant from being saved:</h4>
+    <h4><%= pluralize(@participant.errors.count, "error") %> prohibited this participant from being saved:</h4>
     <ul>
-        <% participant.errors.full_messages.each do |message| %>
+      <% @participant.errors.full_messages.each do |message| %>
         <li><%= message %></li>
       <% end %>
     </ul>

db/migrate/20240206215026_add_indexes_to_employers.rb

@@ -0,0 +1,6 @@
+class AddIndexesToEmployers < ActiveRecord::Migration[7.0]
+  def change
+    add_index :employers, :ssn, unique: true
+    add_index :employers, :tin, unique: true
+  end
+end

db/migrate/20240206215704_add_indexes_to_workers.rb

@@ -0,0 +1,5 @@
+class AddIndexesToWorkers < ActiveRecord::Migration[7.1]
+  def change
+    add_index :workers, :ssn, unique: true
+  end
+end

db/migrate/20240206215805_add_indexes_to_vendors.rb

@@ -0,0 +1,5 @@
+class AddIndexesToVendors < ActiveRecord::Migration[7.1]
+  def change
+    add_index :vendors, :tin, unique: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_02_03_002211) do
+ActiveRecord::Schema[7.1].define(version: 2024_02_06_215805) do
   create_table "employer_records", force: :cascade do |t|
     t.integer "participant_id", null: false
     t.integer "employer_id", null: false
@@ -38,6 +38,8 @@ ActiveRecord::Schema[7.1].define(version: 2024_02_03_002211) do
     t.string "city"
     t.string "state"
     t.string "zip"
+    t.index ["ssn"], name: "index_employers_on_ssn", unique: true
+    t.index ["tin"], name: "index_employers_on_tin", unique: true
   end
 
   create_table "employers_vendors", id: false, force: :cascade do |t|
@@ -137,6 +139,7 @@ ActiveRecord::Schema[7.1].define(version: 2024_02_03_002211) do
     t.string "city"
     t.string "state"
     t.string "zip"
+    t.index ["tin"], name: "index_vendors_on_tin", unique: true
   end
 
   create_table "workers", force: :cascade do |t|
@@ -155,6 +158,7 @@ ActiveRecord::Schema[7.1].define(version: 2024_02_03_002211) do
     t.string "city"
     t.string "state"
     t.string "zip"
+    t.index ["ssn"], name: "index_workers_on_ssn", unique: true
   end
 
   add_foreign_key "employer_records", "employers"