diff --git a/dirs/rbac/schema.sql b/dirs/rbac/schema.sql
index 38e71a7..1d3ac1e 100644
--- a/dirs/rbac/schema.sql
+++ b/dirs/rbac/schema.sql
@@ -1,4 +1,4 @@
--- Add new schema named "public"
+            -- Add new schema named "public"
 CREATE SCHEMA IF NOT EXISTS "public";
 -- Set comment to schema: "public"
 COMMENT ON SCHEMA "public" IS 'standard public schema';
@@ -81,7 +81,8 @@ CREATE TABLE "public"."employees" (
   CONSTRAINT "employees_department_id_fkey" FOREIGN KEY ("department_id") REFERENCES "public"."departments" ("id") ON UPDATE NO ACTION ON DELETE RESTRICT,
   CONSTRAINT "employees_salary_positive_chk" CHECK ("salary" >= 15.00),
   CONSTRAINT "employees_salary_reasonable_max_chk" CHECK ("salary" <= 99999999.99),
-  CONSTRAINT "employees_start_date_not_future_chk" CHECK ("start_date" <= CURRENT_DATE)
+  CONSTRAINT "employees_start_date_not_future_chk" CHECK ("start_date" <= CURRENT_DATE),
+  CONSTRAINT "employees_user_id_unique" UNIQUE ("user_id")
 );
 
 -- Create "projects" table