Introduction The Oracle PL/SQL Interactive Workbook, 2nd edition, presents the Oracle PL/SQL programming language in a unique and highly effective format. It challenges you to learn Oracle PL/SQL by using it rather than by simply reading about it. Just as a grammar workbook would teach you about nouns and verbs by first showing you examples and then asking you to write sentences, the Oracle PL/SQL Interactive Workbook teaches you about cursors, loops, procedures, triggers, and so on by first showing you examples and then asking you to create these objects yourself. Who This Book Is For This book is intended for anyone who needs a quick but detailed introduction to programming with Oracle''s PL/SQL language. The ideal readers are those with some relational database experience, with some Oracle experience, specifically with SQL and SQL*Plus, but with little or no experience with PL/SQL or with most other programming languages. The content of this book is based on the material that is taught in an Introduction to PL/SQL class at Columbia University''s Computer Technology and Applications (CTA) program in New York City. The student body is rather diverse, in that there are some students who have years of experience with information technology (IT) and programming, but no experience with Oracle PL/SQL, and then there are those with absolutely no experience in IT or programming. The content of the book, like the class, is balanced to meet the needs of both extremes.
The exercises in this book can be used as lab and homework assignments to accompany the lectures in such a PL/SQL course. How This Book Is Organized The intent of this workbook is to teach you about Oracle PL/SQL by presenting you with a series of challenges followed by detailed solutions to those challenges. The basic structure of each chapter is as follows: Chapter Lab Exercises Exercise Answers (with detailed discussion) Self-Review Questions Lab . Test Your Thinking Questions Each chapter contains interactive labs that introduce topics about Oracle PL/SQL. The topics are discussed briefly and then explored though exercises, which are the heart of each lab. Each exercise consists of a series of steps that you will follow to perform a specific task, along with questions that are designed to help you discover the important things about PL/SQL programming on your own. The answers to these questions are given at the end of the Exercises, along with more in-depth discussion of the concepts explored. The exercises are not meant to be closed-book quizzes to test your knowledge.
On the contrary, they are intended to act as your guide and walk you through a task. You are encouraged to flip back and forth from the exercise question section to the exercise answer section so that, if need be, you can read the answers and discussions as you go along. At the end of each lab is a series of multiple-choice self-review questions. These are meant to be closed-book quizzes to test how well you understood the lab material. The answers to these questions appear in Appendix A. Finally, at the end of each chapter you will find a Test Your Thinking section, which consists of a series of projects designed to solidify all of the skills you have learned in the chapter. If you have successfully completed all of the labs in the chapter, you should be able to tackle these projects with few problems. You will find guidance and/or solutions to these in Appendix D and at the companion Web site.
About The Companion Web Site The companion Web site is located at http://www.phptr.com/rosenzweig2e/ Here you will find two very important things: Files you will need before you begin reading the workbook: all of the exercises and questions are based on a sample database called STUDENT. The files required to create and install the STUDENT schema are downloadable from the Web site. Answers to the Test Your Thinking questions. In addition to required files and Test Your Thinking answers, the Web site will have many other features, like message board and periodically updated information about the book. There may also be some additional PL/SQL assignments without answers that can be used for graded homework. You should visit the companion Web site, download the student schema, and install it in your database.
What You Will Need There are software programs as well as knowledge requirements necessary to complete the exercise sections of the workbook. Note that some features covered throughout the workbook are applicable to Oracle 9i only. However, you will be able to complete a great majority of the exercise sections by using the following products: Software Oracle 7.3.4 or higher SQL*Plus 3.3 or higher Access to the Internet Windows 95/98/2000 or NT 4.0 Oracle 9i Oracle 9i is Oracle''s RDBMS and its flagship product. You can use either Oracle Personal Edition or Oracle Enterprise Edition.
If you use Oracle Enterprise Edition, this can be running on a remote server or locally on your own machine. Oracle 9.0.1.1.1 Enterprise Edition running locally was used to create the exercises for this book, but subsequent versions should be compatible (the Web site will also have scripts to create a database that will function for Oracle 7.3 and above, although features specified as Oracle 9i will not run in versions below Oracle 9). Additionally, you should have access to and be familiar with SQL*Plus.
This book was used running SQL*Plus version 9.0.1.0.1. You have a number of options for how to edit and run scripts from SQL*Plus. There are also many third-party programs to edit and debug PL/SQL code. SQL*Plus is used throughout this book, since SQL*Plus comes with the Oracle Personal Edition and Enterprise Edition 9.
0.1.0.1. Using SQL*Plus You should be familiar with using SQL*Plus to execute SQL statements (if not, then refer to another book in the Prentice Hall Interactive Oracle Series on this topic, Morrison/Rishchert''s Oracle SQL Interactive Workbook, 2nd ed., 2004). There are a few key differences between executing SQL statements in SQL*Plus and executing PL/SQL statements in SQL*Plus. You will be introduced to these differences so that you can work with the exercises in this book.
You can end an SQL Command in SQL*Plus in one of three ways: with a semicolon (;) with a forward slash (/) on a line by itself with a blank line The semicolon (;) tells SQL*Plus that you want to run the command that you have just entered. You type the semicolon at the end of the SELECT statement and then press return. SQL*Plus will process what is in the SQL Buffer (described next). n FOR EXAMPLESQL> SELECT sysdate 2 FROM dual 3 ;SYSDATE---------28-JUL-02SQL> The SQL Buffer SQL*Plus will store the SQL command or PL/SQL block that you have most recently entered in an area of memory known as the SQL Buffer. The SQL Buffer will remain unchanged until you enter a new command or exit your SQL*Plus session. You can easily edit the contents of the SQL Buffer by typing the EDIT command at the SQL prompt. The default text editor will open with the contents of the SQL Buffer. You can edit and save the file and then exit the editor.
This will cause the contents of the SQL Buffer to change to your last saved version. SQL*Plus commands such as SET SERVEROUTPUT ON are not captured into the SQL Buffer, nor does SQL*Plus store the semicolon or the forward slash you type to execute a command in the SQL buffer. When you create stored procedures, functions, or packages, you begin with the CREATE command. When you begin a PL/SQL block, you start by entering the word DECLARE or BEGIN. Typing either BEGIN, DECLARE, or CREATE will put the SQL*Plus session into PL/SQL mode. Running PL/SQL Blocks in SQL*Plus Once you are in PL/SQL mode, you will not be able to end the block in the same manner that you ended a SQL block. The semicolon (;) can be used multiple times in a single PL/SQL block; thus when you end a line with a semicolon you will not terminate the block. You can terminate the PL/SQL block in the SQL Buffer by entering a period (.
). This will end the block and leave the block in the SQL Buffer, but it will not execute it. At this point you have a choice of typing the EDIT command to edit the block or executing it with a forward slash (/) or a SQL*Plus command RUN. n FOR EXAMPLE You may enter and execute a PL/SQL subprogram as follows: SQL> BEGIN 2 DBMS_OUTPUT.PUT_LINE (''This is a PL/SQL Block''); 3 END; 4 .SQL> /This is a PL/SQL BlockPL/SQL procedure successfully completed. If want to run a script file at a later date, you must remember to terminate it with a period (.) and/or forward slash (/) before saving it on your computer.
If you simply want to put the code into the SQL Buffer and then execute it, you can end the script with a forward slash (/). You should terminate PL/SQL blocks stored in the script file with the period if you want to put the code in the SQL Buffer. You should end the script with forward slash (/) if you want the PL/SQL code in the file to execute. The failure to end your PL/SQL block with a period (.) and/or a forward slash (/) will prevent your block from executing. About The Sample Schema The STUDENT schema contains tables and other objects meant to keep information about a registration and enrollment system for a fictitious university. There are ten tables in the system that store data about students, courses, instructors, and so on. In addition to storing contact information (addresses and telephone numbers) for students and instructors, and descriptive information about courses (costs and prere.