diff --git a/packages/bookshop/srv/cat-service.js b/packages/bookshop/srv/cat-service.js
index a5a58f27..c801d646 100644
--- a/packages/bookshop/srv/cat-service.js
+++ b/packages/bookshop/srv/cat-service.js
@@ -2,27 +2,26 @@ const cds = require('@sap/cds')
 const { Books } = cds.entities
 
 /** Service implementation for CatalogService */
-module.exports = cds.service.impl(async function() {
+module.exports = cds.service.impl(async function () {
   const bupaSrv = await cds.connect.to('API_BUSINESS_PARTNER')
-  const { A_BusinessPartnerAddress } = bupaSrv.entities
-  this.after ('READ', 'Books', each => each.stock > 111 && _addDiscount2(each,11))
-  this.before ('CREATE', 'Orders', _reduceStock)
-  this.on('READ', 'Addresses', req => bupaSrv.run(req.query.from(A_BusinessPartnerAddress)))
+  this.after('READ', 'Books', each => each.stock > 111 && _addDiscount2(each, 11))
+  this.before('CREATE', 'Orders', _reduceStock)
+  this.on('READ', 'Addresses', req => bupaSrv.tx(req).run(req.query))
 })
 
 /** Add some discount for overstocked books */
-function _addDiscount2 (each,discount) {
+function _addDiscount2(each, discount) {
   each.title += ` -- ${discount}% discount!`
 }
 
 /** Reduce stock of ordered books if available stock suffices */
-async function _reduceStock (req) {
+async function _reduceStock(req) {
   const { Items: OrderItems } = req.data
-  return cds.transaction(req) .run (()=> OrderItems.map (order =>
-    UPDATE (Books) .set ('stock -=', order.amount)
-    .where ('ID =', order.book_ID) .and ('stock >=', order.amount)
-  )) .then (all => all.forEach ((affectedRows,i) => {
-    if (affectedRows === 0)  req.error (409,
+  return cds.transaction(req).run(() => OrderItems.map(order =>
+    UPDATE(Books).set('stock -=', order.amount)
+      .where('ID =', order.book_ID).and('stock >=', order.amount)
+  )).then(all => all.forEach((affectedRows, i) => {
+    if (affectedRows === 0) req.error(409,
       `${OrderItems[i].amount} exceeds stock for book #${OrderItems[i].book_ID}`
     )
   }))