diff --git a/db/migrate/20241217161720_create_unique_index_on_people_user_id.rb b/db/migrate/20241217161720_create_unique_index_on_people_user_id.rb
new file mode 100644
index 000000000..de2884150
--- /dev/null
+++ b/db/migrate/20241217161720_create_unique_index_on_people_user_id.rb
@@ -0,0 +1,6 @@
+class CreateUniqueIndexOnPeopleUserId < ActiveRecord::Migration[7.0]
+  def change
+    remove_index :people, :user_id
+    add_index :people, :user_id, unique: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index fd84a7870..c1c1e91a9 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2024_12_16_054507) do
+ActiveRecord::Schema[7.0].define(version: 2024_12_17_161720) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "fuzzystrmatch"
   enable_extension "pg_trgm"
@@ -494,7 +494,7 @@
     t.string "country_name"
     t.index ["slug"], name: "index_people_on_slug", unique: true
     t.index ["topic_resource_key"], name: "index_people_on_topic_resource_key", unique: true
-    t.index ["user_id"], name: "index_people_on_user_id"
+    t.index ["user_id"], name: "index_people_on_user_id", unique: true
   end
 
   create_table "projection_assessment_runs", force: :cascade do |t|
diff --git a/erd.pdf b/erd.pdf
index a5e3f772f..e6219763e 100644
Binary files a/erd.pdf and b/erd.pdf differ