Windows IT administrators are typically IT generalists, and as such are responsible for managing a variety of systems and applications. With this responsibility can come the duty of purchasing or maintaining a database product. The good news is that a number of entry-level lightweight database products exist, and they really fill the bill for developers who are learning their way around the database world and Windows administrators who must make product decisions for a small business or a department in a larger organization. Lightweight database products aren't intended for large-scale environments, but they can be great solutions for smaller-scale implementations and one-person operations, and can also meet database-training needs. All the products in this Buyer's Guide, from open-source solutions to Microsoft and Oracle products, can be easily upgraded to the full-featured product line.
Although the number of light database products on the market isn't large, some vendors offer more than one version. For example, both Microsoft SQL Server 2005 Compact Edition and Oracle Database Lite 10g are database products that let you build, test, deploy, and manage applications for mobile devices. These products allow offline data management capabilities to let you access your database and manipulate data while offline. (If the name SQL Server 2005 Compact Edition isn't familiar, that might be because the product was known as SQL Server 2005 Everywhere Edition during its development phase.)
Microsoft, Oracle, and IBM offer free light database products that are great starter databases to develop, deploy, and distribute. These products include SQL Server 2005 Express Edition, the light version of SQL Server 2005; Database 10g Express Edition, the light version of Database 10g Release 2; and IBM DB2 Express-C, the light version of IBM DB2. There are appreciable differences between these three products. For example, DB2 Express-C, unlike the Oracle and Microsoft solutions, places no restrictions on database size. In addition, there are no restrictions to the number of instances or databases per server, and no restriction on the number of users with DB2 Express-C. If supporting user data types is important, you'll need to consider SQL Server Express—Database 10g Express Edition doesn't support user data types.
When evaluating the free solutions, look at their built-in development tools—the functions and capabilities for each product differ. Data protection is always a concern, so evaluate each solution's data protection features. SQL Server Express, for example, has three levels of code-access security: Safe, External Access, and Unsafe. All three of the free solutions are available for download on the vendors' Web sites.
Two open-source light database solutions are well accepted and in use in many organizations. MySQL is used by Yahoo!, NASA, and The Associated Press. PostgreSQL is used by a number of large universities, including the University of California at Berkeley and the University of Alabama, Birmingham, as well as in organizations such as Cisco and Sun Microsystems. Open-source database systems number reduced licensing costs and lower hardware expenditures among their benefits.
Windows or Linux?
The OSs that are installed in your environment will affect your choice of light database solution. If you're a Windows shop, you can choose among all of the solutions listed in the product table on page XX. If you support Windows and Linux or only Linux, you'll need to look at solutions other than SQL Server Express or SQL Server 2005 Compact Edition. The open-source solutions PostgreSQL and MySQL support the greatest number of OSs. If you're a heterogeneous shop, consider those products.
A variety of database functions will come into play as you evaluate solutions. If you want a product that supports user-defined functions, triggers, user-data types, or stored procedures, use the product table to identify which of those functions each product supports. Although most vendors support database functions, a few do not. Another important factor is database maximum size. The proprietary solutions, such as SQL Server Express, SQL Server 2005 Compact Edition, Database 10g Express Edition, and Database Lite 10g, let you create databases as large as 4GB. However, DB2 Express-C, PostgreSQL, and MySQL impose no limits on database size.