diff --git a/db/migrate/20211127133549_create_zones.rb b/db/migrate/20211127133549_create_zones.rb
index d98b30b2d..f3a54c108 100644
--- a/db/migrate/20211127133549_create_zones.rb
+++ b/db/migrate/20211127133549_create_zones.rb
@@ -1,7 +1,7 @@
 class CreateZones < ActiveRecord::Migration[6.1]
   def change
     create_table :zones do |t|
-      t.string :acronym
+      t.string :acronym, null: false, index: { unique: true }
       t.string :label
 
       t.timestamps
diff --git a/db/schema.rb b/db/schema.rb
index 6c8fad2c6..64a46604c 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -554,6 +554,14 @@ ActiveRecord::Schema.define(version: 2021_11_27_143736) do
     t.index ["user_id"], name: "index_merge_logs_on_user_id"
   end
 
+  create_table "zones", force: :cascade do |t|
+    t.string "acronym", null: false
+    t.string "label"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["acronym"], name: "index_zones_on_acronym", unique: true
+  end
+
   create_table "module_api_cartos", id: :serial, force: :cascade do |t|
     t.integer "procedure_id"
     t.boolean "use_api_carto", default: false
@@ -825,13 +833,6 @@ ActiveRecord::Schema.define(version: 2021_11_27_143736) do
     t.index ["procedure_id"], name: "index_without_continuation_mails_on_procedure_id"
   end
 
-  create_table "zones", force: :cascade do |t|
-    t.string "acronym"
-    t.string "label"
-    t.datetime "created_at", precision: 6, null: false
-    t.datetime "updated_at", precision: 6, null: false
-  end
-
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
   add_foreign_key "archives_groupe_instructeurs", "archives"
   add_foreign_key "archives_groupe_instructeurs", "groupe_instructeurs"