Add uniqueness validation to document_number and document_type pair

app/models/local_census_record.rb

@@ -5,6 +5,7 @@ class LocalCensusRecord < ApplicationRecord
   validates :document_type, presence: true
   validates :date_of_birth, presence: true
   validates :postal_code, presence: true
+  validates :document_number, uniqueness: { scope: :document_type }
 
   scope :search,  -> (terms) { where("document_number ILIKE ?", "%#{terms}%") }
 

db/migrate/20190530082138_add_unique_index_to_local_census_records.rb

@@ -0,0 +1,9 @@
+class AddUniqueIndexToLocalCensusRecords < ActiveRecord::Migration[5.0]
+  def up
+    add_index :local_census_records, [:document_number, :document_type], unique: true
+  end
+
+  def down
+    remove_index :local_census_records, [:document_number, :document_type]
+  end
+end

db/schema.rb

@@ -978,6 +978,7 @@ ActiveRecord::Schema.define(version: 20190607160900) do
     t.string   "postal_code",     null: false
     t.datetime "created_at",      null: false
     t.datetime "updated_at",      null: false
+    t.index ["document_number", "document_type"], name: "index_local_census_records_on_document_number_and_document_type", unique: true, using: :btree
     t.index ["document_number"], name: "index_local_census_records_on_document_number", using: :btree
   end
 

spec/models/local_census_record_spec.rb

@@ -32,6 +32,14 @@ describe LocalCensusRecord do
       expect(local_census_record).not_to be_valid
     end
 
+    it "is not valid when a record already exists with same document_number and document_type" do
+      create(:local_census_record, document_number: "#DOC_NUMBER", document_type: "#DOC_TYPE")
+      local_census_record = build(:local_census_record, document_number: "#DOC_NUMBER",
+        document_type: "#DOC_TYPE")
+
+      expect(local_census_record).not_to be_valid
+    end
+
     it "sanitizes text attributes values before validation" do
       local_census_record.document_type = " DNI "
       local_census_record.document_number = " #DOCUMENT_NUMBER "