Beginning Oracle Application Express

Oracle Application Express is an easy-to-use application development environment built on the Oracle technology stack. There are two aspects of that previous sentence that you may find jarring—that Oracle, a company widely known for its database technology, has an application development environment, and that Oracle, a company thought of as delivering high-end, enterprise-ready technology, has anything that is easy to use.

But, as this book will show, the introductory statement is completely accurate. Oracle Application Express, commonly known as Oracle APEX or simply APEX, does benefit from the long-established enterprise-class robustness that is the hallmark of Oracle technology. The applications you build will be able to support hundreds of users and many terabytes of data, scalability far beyond even the imagination of most other development environments.

And Oracle APEX, with its declarative, wizard-driven methodology, is truly easy to use. In the course of the few hundred pages of this book, you will not only learn about how to use APEX, you will create a usable order entry system. The fast learning curve presented in these pages is a consequence of many years of development and refinement of the APEX product, which began life almost a decade ago within Oracle.

By the end of this volume, you will know enough to create your own applications, as well as having the knowledge and understanding of Oracle APEX and the world of Oracle technology to explore further refinements on your own.

Best of all, you can use APEX with absolutely no cost—either in a hosted environment, as suggested in Chapter 1, or with a free version of the Oracle database.

Welcome to the world of Oracle Application Express!

This book is aimed at a particular group of users—those who are not familiar with Oracle Application Express. The book assumes that you have a basic knowledge of application development, the type you could get from playing around with a personal database such as Access. In fact, this book was written with an Access developer in mind—an Access developer looking to step up to a more scalable and reliable environment, with reduced maintenance overhead and greater integration between application systems.

This book covers the use of Oracle Application Express. Although the book is based on the 3.5 version, you can use the book with older versions as well. However, since the book will use a hosted version of Oracle Application Express, and since both the Oracle database that support the product and the product itself are available as free downloads from http://otn.oracle.com, you should be able to use the latest version easily.

This book is structured to give the reader a gradual introduction to the essentials of development with Oracle Application Express. The book contains the following:

• Welcome to Oracle!—This contains an overview of Oracle Application Express, as well as instructions on how to set up a hosted development environment for performing the exercises used in the book.

• Jumpstart Oracle Application Express—You will leap into creating applications with Oracle Application Express and finish a simple application by the end of this.

• Extending Your Oracle APEX Application—This will introduce you to the options in Oracle APEX that let you ensure that your users will enter correct data while using your application.

• Validation, Calculation, Navigation, and Lists—This continues the exploration of the aspects of APEX that help you to ensure that data used in your application is correct. Additionally, this covers basic navigation options for your application.

• Reporting and Charting—This covers the powerful and flexible reports you can create with Oracle APEX, and introduces you to the graphical capabilities of APEX reporting.

• Components Working Together—This extends your work with charts, showing how you can create charts that link to a more detailed view of the data they represent. You will also learn how to create a calendar page with links to the data shown as part of the calendar, and how to add images taken from the underlying database to an Oracle APEX report.

• Customizing User Interfaces—This explores advanced options for customizing user interfaces, on individual pages as well as across your entire APEX application.

• PL/SQL—This introduces you to PL/SQL, the underlying language used to implement your APEX application, and demonstrates how to use the power of PL/SQL to extend the logic in your application.

• Security—This covers how security is implemented for your APEX environment.

• Deployment and Administration—This covers the options you have for deploying an APEX application to another environment and walks you through one of those options. Additionally, this introduces you to the administrative functionality you can use to monitor and manage your APEX applications.

• Packaged Applications—This gives an overview of packaged applications available for Oracle Application Express, with a more detailed look at a select few.

• Migration—This describes how to migrate applications from Microsoft Access to Oracle Application Express.

Oracle Application Express是建立在Oracle技術堆疊上的易於使用的應用程式開發環境。在前一句中，有兩個方面可能讓您感到不舒服：一是Oracle，這家以其資料庫技術而聞名的公司，擁有一個應用程式開發環境；二是Oracle，這家被認為提供高端企業級技術的公司，擁有易於使用的東西。

但是，正如本書將展示的那樣，這個開場白是完全準確的。Oracle Application Express，通常稱為Oracle APEX或簡單地APEX，確實受益於Oracle技術所具有的長期企業級穩定性。您建立的應用程式將能夠支持數百個用戶和數TB的數據，可擴展性遠遠超出大多數其他開發環境的想像。

而Oracle APEX以其聲明性、向導驅動的方法論，確實易於使用。在本書的幾百頁中，您不僅將學習如何使用APEX，還將創建一個可用的訂單輸入系統。這些頁面中呈現的快速學習曲線是APEX產品多年開發和改進的結果，該產品在近十年前在Oracle內部誕生。

通過閱讀本書，您將掌握足夠的知識來創建自己的應用程式，並了解Oracle APEX和Oracle技術世界，以進一步探索自己的改進。

最重要的是，您可以完全免費使用APEX，無論是在托管環境中（如第1章所建議的）還是使用免費版本的Oracle資料庫。

歡迎來到Oracle Application Express的世界！

本書針對一個特定的用戶群體，即那些不熟悉Oracle Application Express的用戶。本書假設您具有基本的應用程式開發知識，這些知識可以通過使用個人資料庫（如Access）進行實驗獲得。事實上，本書是針對Access開發人員撰寫的，他們希望轉向更可擴展和可靠的環境，並減少維護工作量，實現應用系統之間更好的集成。

本書介紹了使用Oracle Application Express的方法。雖然本書基於3.5版本，但您也可以使用舊版本。然而，由於本書將使用托管版本的Oracle Application Express，並且支持該產品的Oracle資料庫和產品本身都可以從http://otn.oracle.com免費下載，因此您應該能夠輕鬆使用最新版本。

本書的結構旨在逐步介紹Oracle Application Express開發的基本要素。本書包含以下內容：
- 歡迎來到Oracle！- 這包含了Oracle Application Express的概述，以及有關如何設置托管開發環境以進行本書中使用的練習的指示。
- 快速入門Oracle Application Express- 您將開始使用Oracle Application Express創建應用程式，並在本書結束時完成一個簡單的應用程式。
- 擴展您的Oracle APEX應用程式- 這將介紹Oracle APEX中的選項，讓您確保用戶在使用應用程式時輸入正確的數據。
- 驗證、計算、導航和列表- 這將繼續探索幫助您確保應用程式中使用的數據正確性的APEX方面。此外，還介紹了應用程式的基本導航選項。
- 報告和圖表- 這將介紹您可以使用Oracle APEX創建的強大靈活的報告，並向您介紹圖形功能。