Chapter 21.  I/O and PL/SQL

Chapter 21. I/O and PL/SQL Many, perhaps most, of the PL/SQL programs we write need to interact only with the underlying Oracle RDBMS using SQL. However, there will inevitably be times when you will want to send information from PL/SQL to the external environment, or read information from some external source (screen, file, etc.) into PL/SQL. This chapter explores some of the most common mechanisms for I/O in PL/SQL, including the following built-in packages: DBMS_OUTPUT For displaying information on the screen UTL_FILE For reading and writing operating system files UTL_MAIL and UTL_SMTP For sending email from within PL/SQL UTL_HTTP For retrieving data from a web page It is outside the scope of this book to provide full reference information about the built-in packages introduced in this chapter. Instead, in this chapter, we'll demonstrate how to use them to handle the most frequently encountered requirements. Check out Oracle's documentation for more complete coverage. You will also find Oracle Built-in Packages (O'Reilly) a helpful source for information on some of the older packages; we have put several chapters from that book on this book's web site.