History and background
APEX is a very powerful development tool, which is used to create web-based database-centric applications. The tool itself consists of a schema in the database with a lot of tables, views, and PL/SQL code. It's available for every edition of the database. The techniques that are used with this tool are PL/SQL, HTML, CSS, and JavaScript.
Before APEX there was WebDB, which was based on the same techniques. WebDB became part of Oracle Portal and disappeared in silence. The difference between APEX and WebDB is that WebDB generates packages that generate the HTML pages, while APEX generates the HTML pages at runtime from the repository. Despite this approach APEX is amazingly fast.
Because the database is doing all the hard work, the architecture is fairly simple. We only have to add a web server. We can choose one of the following web servers:
Oracle HTTP Server (OHS)
Embedded PL/SQL Gateway (EPG)
APEX Listener
APEX became available to the public in 2004 and then it was part of version 10g of the database. At that time it was called HTMLDB and the first version was 1.5. Before HTMLDB, it was called Oracle Flows, Oracle Platform, and Project Marvel. Throughout the years many versions have come out and at the time of writing the current version is 4.1.1. These many versions prove that Oracle has continuously invested in the development and support of APEX. This is important for the developers and companies who have to make a decision about which techniques to use in the future. According to Oracle, as written in their statement of direction, new versions of APEX will be released at least annually. The following screenshot shows the home screen of the current version of APEX:
Home screen of APEX
For the last few years, there is an increasing interest in the use of APEX from developers. The popularity came mainly from developers who found themselves comfortable with PL/SQL and wanted to easily enter the world of web-based applications. Oracle gave ADF a higher priority, because APEX was a no cost option of the database and with ADF (and all the related techniques and frameworks from Java), additional licenses could be sold.
Especially now Oracle has pointed out APEX as one of the important tools for building applications in their Oracle Database Cloud Service, this interest will only grow. APEX shared a lot of the characteristics of cloud computing, even before cloud computing became popular. These characteristics include:
Elasticity
Roles and authorization
Browser-based development and runtime
RESTful web services (REST stands for Representational State Transfer)
Multi-tenant
Simple and fast to join
APEX has outstanding community support, witnessed by the number of posts and threads on the Oracle forum. This forum is the most popular after the database and PL/SQL.
Oracle itself has some websites, based on APEX. Among others there are the following:
Oracle uses quite a few internal APEX applications.
Oracle also provides a hosted version of APEX at http://apex.oracle.com. Users can sign up for free for a workspace to evaluate and experiment with the latest version of APEX. This environment is for evaluations and demonstrations only, there are no guarantees! Apex.oracle.com is a very popular service—more than 16,000 workspaces are active. To give an idea of the performance of APEX, the server used for this service used to be a Dell Poweredge 1950 with two Dual Core Xeon processors with 16 GB.
To get a jumpstart with developing real-life APEX applications, we have written this book and provided you with some best practices. These practices don't have to be appropriate in all situations, see them as guidelines. This book is not intended as a point and click starters guide and assumes a basic understanding of APEX, PL/SQL, HTML, and CSS.
