Oracle PL/SQL Programming: A Developer's Workbook

Expert

22-19.

Write a package that manages communication through a private pipe named “invasions”. Each message in the pipe contains the information as specified by the following query: SELECT country, date_of_invasion, people_killed FROM invasions WHERE (invader IN ('USA', 'CHINA', 'GERMANY', 'SOVIET UNION') AND date_of_invasion > '01-JAN-1900'; Features of this package should include the following: The user never specifies or knows the name of the pipe; it is hidden to avoid any spelling mistakes and to ensure consistency. It create the pipe automatically when a session tries to use the pipe. The list is a long one (including, for example, Grenada, Poland, Nicaragua, Vietnam, Chile, France, Tibet, Norway, El Salvador, and Iraq), so set the initial pipe size to at least 2 MB. It waits up to 10 seconds to get or send the information. Here is the package specification; you write the body: /* Filename on web page: invasions.pkg */ CREATE OR REPLACE PACKAGE invasion IS TYPE inv_rectype IS RECORD ( country IN invasions.country%TYPE, date_of_invasion invasions.date_of_invasion%TYPE, people_killed invasions.people_killed%TYPE ); PROCEDURE sendinfo ( country IN VARCHAR2, date_of_invasion DATE, people_killed NUMBER ); PROCEDURE sendinfo (rec IN inv_rectype); FUNCTION nextinfo RETURN inv_rectype; END; /

22-20.

How can you can obtain a list of all the currently defined database pipes to which you have ...