Oracle PL/SQL Programming: A Developer's Workbook

Expert

27-30.	The DBA for your site has added the required entries in the LISTENER.ORA and TNSNAMES.ORA files, but you are still not able to communicate with your external procedures. Is there anything else that you or your DBA should check to ensure that the new information is active?
27-31.	Here is another extensive case study for you to develop involving sending email from a Unix server: Suppose that you currently work for the company Widgets R Us and are involved in building a long-awaited, brand-new automated system. One of the services this new system will offer to customers is that they can be notified by email of any new products being produced by your company. Your System Architect has done a wonderful job and has produced a perfectly normalized model, which has an entity that contains high-level information about all the products currently offered by the company (products table). For the sake of this example, assume that email addresses of the clients who wish notification are contained in a table called clients_to_notify. Describe all the tasks needed to implement the email notification component of the system using external procedures, and write the necessary PL/SQL code.
27-32.	extproc is currently implemented by Oracle as a single-threaded process. As a developer, what concerns would you have if, in future releases, Oracle decided to implement external procedures in a multithreaded manner?
27-33.	Can external program calls be debugged?