diff --git a/examples/demo-app/src/lib/db.ts b/examples/demo-app/src/lib/db.ts
new file mode 100644
index 0000000..c169064
--- /dev/null
+++ b/examples/demo-app/src/lib/db.ts
@@ -0,0 +1,30 @@
+export interface User {
+  id: string;
+  email: string;
+  passwordHash: string;
+}
+
+export interface Order {
+  id: string;
+  userId: string;
+  amount: number;
+}
+
+export const db = {
+  user: {
+    findUnique: async (query: { where: { id: string } }) => {
+      return { id: query.where.id, email: 'alex@example.com', passwordHash: '$2b$10$e8...' };
+    }
+  },
+  order: {
+    findUnique: async (query: { where: { id: string } }) => {
+      return { id: query.where.id, userId: 'user-123', amount: 99.99 };
+    },
+    findMany: async () => {
+      return [{ id: 'order-1', userId: 'user-123', amount: 49.0 }];
+    }
+  },
+  query: async (sql: string) => {
+    return { rows: [{ id: '1', sql }] };
+  }
+};