| Developer(s) | Oracle Corporation |
|---|---|
| Stable release | 4.1 / August 24, 2011 |
| Operating system | Linux and Windows |
| Type | Oracle database development environment |
| License | Oracle Technical Network License (Proprietary) |
| Website | http://apex.oracle.com |
Oracle Application Express (Oracle APEX, previously named Oracle HTML DB) is a software development environment based on the Oracle database.[1] It allows a fast development cycle to be achieved to create web based applications. It can be used for departmental-style applications with a dozen users, but can also scale up to handle thousands of users. The framework itself adds as little as 0.04 second of overhead to each page request;[2] how well an application scales is primarily based on the efficiency of the SQL queries used by the application developer.
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Oracle Application Express can be installed in an Oracle 9.2 or higher database, and starting from Oracle 11g it will be preinstalled along with the database. APEX 4.0 and higher can be installed on an Oracle 10.2.0.3 or higher database.
In January 2006 Oracle renamed HTML DB to "Oracle Application Express". Version 2.1 of APEX was bundled with the free Oracle Express Edition (XE) database.
In 2007 Oracle released APEX 3.0. This third major version features several new features, notably PDF Printing and Flash charting. APEX 3.0.1 was released in July 2007, and this version can also be installed into an Oracle XE database.
In Spring 2008 Oracle released APEX 3.1. This included a new major feature known as Interactive Reporting, which enables end-users to extensively customize a report without programmer intervention, using techniques such as filtering, sorting, group-by, choosing displayed columns, etc. The user can even save multiple versions of their customized reports. The programmer can limit which features are enabled. With this power comes a loss of programmer control over the layout of the report.
APEX 4.0 became available in June 2010. Some notable features are declarative dynamic actions which allow reacting to changes on a page without the developer having to write the javascript and RESTful capabilities.
Historically speaking, Application Express has gone through many name changes since its inception in 2000. A reasonably complete history of the names includes:
One popular misconception is that Application Express is a new version of Web DB. Mike Hichwa created Web DB, a successful web front-end for Oracle, but the development of Web DB started to move in a direction that diverged from Mike's vision. When tasked with building an internal web calendar, Mike enlisted the help of Joel Kallman and started "Flows". They co-developed the Web Calendar and Flows, adding features to Flows as they needed them to develop the calendar. In the earliest days of Flows, there was no front-end for it, so all changes to an application were made in SQL*Plus via inserts, updates and deletes. In some ways APEX is an evolution of Web DB, but it was developed with new code and no upgrade path.
A popular application developed in Application Express is the AskTom application developed by Thomas Kyte. Oracle's Metalink support site had been running on APEX, but was replaced with a Flash version in September 2008.[3] Oracle's online store also runs on APEX.
There is a common misconception that the abstracted nature of APEX applications results in a relatively secure user environment. However, APEX applications suffer from the same classes of application security flaws as other web applications based on more direct technologies such as PHP, ASP.net and Java.
The main classes of vulnerability that affect APEX applications are: SQL injection, Cross-site scripting (XSS), and Access Control.
APEX applications inherently use PL/SQL constructs as the base server-side language. As well as accessing data via PL/SQL blocks, an APEX application will use PL/SQL to implement authorization, and to conditionally display web page elements. This means that generally APEX applications suffer from SQL injection when these PL/SQL blocks do not correctly validate and handle malicious user input. Oracle implemented a special variable type for APEX called Substitution Variables (with a syntax of &NAME.) and these are not safe and lead to SQL Injection. Where the injection occurs within a PL/SQL block an attacker can inject an arbitrary number of queries or statements to execute.
Cross-Site Scripting vulnerabilities arise in APEX applications just like other web application languages. Oracle provide the htf.escape_sc() function to escape user data that is displayed within a rendered HTML response. The reports that APEX generates also provide protection against XSS through the Display As setting on report columns. Originally the default was for reports to be created without any escaping of the columns, although recent versions now set the column type to escape by default. Column definitions can be queried programmatically to check for columns that do not escape the value.
To control access to resources within an APEX application a developer can assign authorization schemes to resources (such as pages and items). These must be applied consistently in order to ensure that resources are appropriately protected. A typical example of inconsistent access-control being applied is where an authorization scheme is set for a Button item, but not the associated Process that is performed when the button is clicked. A malicious user can perform the process (through JavaScript) without requiring the actual Button to be accessible.
Since APEX 4.0, the Application Builder interface provides some limited assessment of the security posture through the Advisor utility.
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