Oracle Database XE's value is not necessarily limited to novices, students, hobbyists, or small businesses—it also holds appeal for many other situations.
Published March 2006
Unless you're doing your best to avoid the news, you've probably heard about the production release of Oracle Database 10g Express Edition (XE), a free starter database for DBAs and developers. This release is truly a historic one from Oracle.
Oracle Database XE's value is not necessarily limited to novices, students, hobbyists, or small businesses, however; it also holds appeal for many other situations. Rather, it will bring value to DBAs, developers, and analysts in the course of their everyday jobs, regardless of the size of their business.
Specifically, if you are a DBA and have users who want to play "what-if" scenarios in your database, Oracle Database XE enables a strategy whereby you can push data out to your user, where it does the most good (and your servers the least harm). Deploying that product can also offer a solution to the common problem of users or developers downloading and installing open-source databases, which leaves you with a minefield of maintenance, support, and security headaches.
If you are a developer who yearns to learn "DBA" tasks or just wants an R&D database to try out new things—or if you're simply tired of open-source incompatibility and migration issues when your application needs to scale—Oracle Database XE is your best alternative.
Finally, if you are a business analyst who needs to play "what-if" but can't do what you need in your warehouse or application of choice, Oracle Database XE can augment your spreadsheets and models and give you reliable, secure access to the data you need.
In this article, I will overview some of the obvious as well as less obvious ways Oracle Database XE can add value for these three roles. But before we begin, it's important to understand Oracle Database XE's inherent limitations.
In order to make this release easy to install (e.g., via the standard Windows Installer), configure, and maintain, Oracle has built certain limitations into the product.
The first limitation is memory—Oracle Database XE can address only 1GB of RAM. But when you consider the relative rarity of machines that offer 1GB of memory (especially in small businesses), this limitation should mainly affect how many users can access the database concurrently and, to a certain degree, how well it will perform when those limits are hit. For most purposes Oracle Database XE will be deployed to a single user desktop or small workgroup server, so 1GB is more than enough.
The second limit is that XE will only use one CPU. That does not mean that it won't multi-task or that it can only perform a single function at a time. Rather, XE will run on a computer with more than one CPU, it just won't scale up to use those CPUs. For that functionality, you need to purchase Oracle Database Standard Edition or Enterprise Edition. Again, for the uses discussed here, one CPU is more than enough.
The third limit is that only a single XE database can run on any given computer. The important point here is that you don't need a database for each application you create, as you might for some competing databases. Instead, Oracle uses the concept of schemas to separate applications.
Finally, a 4GB limit is enforced on disk space—which on its face appears to be serious limitation. However, 4GB is a huge amount of storage for most applications. Sure, compared to a multi-terabyte data warehouse, 4GB seems small—but in reality it's hardly that.
Consider the included HR sample schema. The maximum row size of the EMPLOYEES table is 144 bytes. Four gigabytes is 4,294,967,296 bytes; 4GB/144 =29,826,162. That means you could store almost 30 million employee records. That's a lot of employees. Even accounting for JOBS, DEPARTMENTS, and the other sample tables, you would not want to store that much data locally. (That's why you pay for an enterprise license.) Oracle Database XE is designed to store only a useful subset of that data.
Not Just a Starter Database
Despite the benefits I've described here, Oracle Database XE is not a panacea. If you have major privacy or compliance requirements, your data should reside in a data center where it can be secured and audited. When you need to support large numbers of users, or if XE is running out of available disk space, your database should be managed and maintained by a DBA in a controlled environment.
But for so many other situations—not simply for training or testing—XE is a wonderful new tool. From mom-and-pop to Fortune 500, you're likely to find that XE is the database for your desktop.