Although this tutorial is about SQL Server, you may want to know about some of the other SQL-based relational database management systems. Figure 1-9 compares three of the most popular, Oracle, DB2, and MySQL, with SQL Server.
Oracle has a huge installed base of customers and continues to dominate the marketplace, especially for servers running the Unix operating system. Oracle works well for large systems and has a reputation for being extremely reliable, but also has a reputation for being expensive and difficult to use.
DB2 was originally designed to run on IBM mainframe systems and continues to be the premier database for those systems. It also dominates in hybrid environments where IBM mainframes and newer servers must coexist. Although it has a reputation for being expensive, it also has a reputation for being reliable and easy to use.
MySQL runs on all major operating systems and is widely used for web applications. MySQL is an open-source database, which means that any developer can view and improve its source code. In addition, the MySQL Community Server is free for most users, although Oracle also sells an Enterprise Edition of MySQL that has advanced features.
SQL Server was designed by Microsoft to run on Windows and is widely used for small- to medium-sized departmental systems. It has a reputation for being inexpensive and easy to use. However, it also has a reputation for being unreliable and for not scaling well for systems with a large number of users.
One of the main differences between SQL Server and the other database management systems is that SQL Server runs only under the Windows operating system. In contrast, Oracle, DB2, and MySQL run under most operating systems, including Unix, Windows, Mac OS, and IBM’s z/OS. Since many developers consider z/OS and Unix to be more stable and secure than Windows, most large companies use z/OS or Unix as the operating system for the servers that store the databases for mission-critical applications. As a result, they can’t use SQL Server and must use Oracle, DB2, or MySQL.
If you search the Internet, you’ll find that dozens of other relational database products are also available. These include proprietary databases like Informix, Sybase, and Teradata. And they include open-source databases like PostgreSQL.
A comparison of Oracle, DB2, MySQL, and SQL Server
|OS/390, Z/OS, and AIX
- Oracle is typically used for large, mission-critical systems that run on one or more Unix servers.
- DB2 is typically used for large, mission-critical systems that run on legacy IBM mainframe systems using the z/OS or OS/390 operating system.
- MySQL is a popular open-source database that runs on all major operating systems and is commonly used for web applications.
- SQL Server is typically used for small- to medium-sized systems that run on one or more Windows servers.