ステップ 1: データベーストリガを作成する

1trigger DeleteRestrictInvoice on Invoice__c (before delete) {
2
3// create a list of Invoices in Trigger.oldMap along with their Line Items
4List<Invoice__c> invoices = [Select i.Name, (Select Name From Line_Items__r)
5										From Invoice__c i
6										Where i.Id IN :Trigger.oldMap.keySet()];
7
8// loop through the Invoices, attaching errors to those that have Line Items
9for (Invoice__c invoice : invoices) {
10	   if (!invoice.Line_Items__r.isEmpty()) {
11      Trigger.oldMap.get(invoice.id).addError('Cannot delete Invoice with Line Items');
12      }
13   }
14}