Harden assignment rules

backend/src/main/resources/dev/seed_demo_customer_pets.sql

@@ -0,0 +1,53 @@
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Rocky', 'dog', 'Labrador', NULL
+FROM customer c
+WHERE c.email = 'alex@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Rocky'
+  );
+
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Whiskers', 'cat', 'Persian', NULL
+FROM customer c
+WHERE c.email = 'emily@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Whiskers'
+  );
+
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Daisy', 'dog', 'Beagle', NULL
+FROM customer c
+WHERE c.email = 'james@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Daisy'
+  );
+
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Pepper', 'cat', 'Domestic Shorthair', NULL
+FROM customer c
+WHERE c.email = 'olivia@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Pepper'
+  );
+
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Cooper', 'dog', 'Golden Retriever', NULL
+FROM customer c
+WHERE c.email = 'william@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Cooper'
+  );
+
+INSERT INTO customer_pet (customer_id, pet_name, species, breed, image_url)
+SELECT c.customerId, 'Mittens', 'cat', 'Siamese', NULL
+FROM customer c
+WHERE c.email = 'sophia@gmail.com'
+  AND NOT EXISTS (
+      SELECT 1 FROM customer_pet cp
+      WHERE cp.customer_id = c.customerId AND cp.pet_name = 'Mittens'
+  );