The code should be altered to collect the insert method return value as a SaveResult variable, which can provide information about the success or failure of the insert operation, as well as any errors that occurred. The SaveResult variable can be used to print the error messages or debug logs, or to perform conditional logic based on the outcome of the insert operation. For example, the code can be modified as follows:
Account a = new Account(Name = 'A'); SaveResult sr = Database.insert(a, false); if (sr.isSuccess()) { System.debug('Account inserted successfully'); } else { System.debug('Account insertion failed: ' + sr.getErrors()[0].getMessage()); } The second parameter of the Database.insert method is the allOrNone option, which specifies whether to roll back the entire transaction or not if any record fails to insert. Setting it to true or false does not affect the debugging of the issue, but only the behavior of the transaction. Adding a System.debug() statement before the insert method does not help to debug the issue, because it does not provide any information about the insert operation itself. Adding a try/catch around the insert method can help to handle any exceptions that may occur during the insert operation, but it does not provide the same level of detail as the SaveResult variable.
References: SaveResult Class, Database.insert method, Prepare for Your Salesforce Platform Developer I Credential