diff --git a/postgres/init.sql b/postgres/init.sql
index f1eca21..f4132ef 100644
--- a/postgres/init.sql
+++ b/postgres/init.sql
@@ -22,14 +22,14 @@ CREATE TABLE startup (
     description text,
     city text NOT NULL,
     state text NOT NULL,
+    created_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (id)
 );
 
 CREATE TABLE startup_membership (
-    id uuid UNIQUE NOT NULL DEFAULT uuidv7(),
-    user_id uuid REFERENCES user_account(id),
-    startup_id uuid REFERENCES startup(id),
-    PRIMARY KEY (id)
+    user_id uuid REFERENCES user_account(id) ON DELETE CASCADE,
+    startup_id uuid REFERENCES startup(id) ON DELETE CASCADE,
+    PRIMARY KEY (user_id, startup_id)
 );
 
 CREATE TYPE investor_kind AS enum (