Introduction to Databases

Commercial RDBMS Systems

We have now covered most of the basics of relational databases. They are the most common database type out there, in addition to being one of the most important types of software, right up there with operating systems, office productivity and games. So it will come as no surprise to hear that the large, successful RDBMS vendors are some of the titans of the software industry, and are also household names not only in the software world, but even in mainstream news and culture. Names like Oracle and Microsoft are ubiquitous and very familiar, even to non-IT types.
Many RDBMS vendors also churn out both related and completely unrelated products. But a common thread for all of them is that the RDBMS is one of their most crucial product lines. They listen closely and work to gather feedback from the marketplace, which does not always happen in the software universe.

However, for strategic business reasons, many of their products do not work well with competitors’ offerings, or with other software. For instance SQL Server from Microsoft is only available for the Windows operating system, which is also from Microsoft. There have been complaints that Oracle DB does not mesh as well with the Windows operating system as it does with Linux, and so on.

An increasing trend in the industry is consolidation and bundling of the RDBMS with other software from the same manufacturer, such as a preferred operating system or other complementary software such as:

  • Additional data security modules, such as Oracle DataGuard,
  • Integration with a development platform, such as Microsoft’s .NET,
  • All-in-one platforms combining hardware and software, such as Oracle’s Exadata or Microsoft’s Trefis.
We will now take a quick look at some commercial RDB offerings and the companies behind them:


Oracle is one of the behemoths of the RDBMS world. Founded by the charismatic, adventure-loving CEO Larry Ellison in 1977, today the company is a multibillion dollar giant in the world of commercial databases thanks to its flagship product, Oracle DB. Oracle also produces a bewildering array of other products, from middleware to enterprise resource planning systems and customer relationship management (CRM) offerings. Many of these were not developed in-house, but instead came through acquisitions of other software companies such as PeopleSoft, Siebel Systems, Sun Microsystems and BEA Systems. Several of these products were integrated, with mixed success, into the Fusion middleware product.

The Oracle DB is widely used in enterprise-level databases. It comes in different editions to meet different needs. Oracle DB is fully compliant with the SQL language, although it also maintains its proprietary version called SQL*Plus. Oracle DB is the leading RDBMS, with a market share of 48.8 percent of the RDBMS market as at end of 2011.

An interesting point to note about Oracle is that in 2009, it acquired Sun Microsystems, the license holder of MySQL, one of Oracle DB’s key competitors. As a result, Oracle has two RDBMS offerings. However, Oracle DB and MySQL may not interfere destructively with each other, as they play in slightly different market spaces and cater to slightly different needs.


Microsoft is another big boy in the world of RDBMS software with its SQL Server product, although it is better known for its universal Windows operating system and Office suite of office-productivity programs.

SQL Server was developed in conjunction with Sybase systems around 1989, but the two companies parted ways and developed separate products. Microsoft kept the SQL Server name and Sybase opted to rename its offering Adaptive Server Enterprise to avoid confusion with Microsoft’s SQL Server. The RDBMS only runs on the Windows range of operating systems.

SQL Server uses a proprietary query language called T-SQL, which is very similar to and compatible with the standard SQL. The RDBMS commands about 20 percent of market share as of the end of 2011, but has also been increasing its share in recent years.

SQL Server and Oracle DB have a lot in common, ranging from the data structures to transaction processing methods and database objects. Like Oracle DB, SQL Server also supports advanced ETL (Extraction, Transformation, Loading) operations, which help in moving data to data warehouses. Both also offer advanced reporting functionality.


Postgres, also known as PostgreSQL, is an open-source relational database that can also support database objects. It is not owned by any one person, but is maintained by the PostgreSQL Global Development Group, a dedicated group of volunteers managed and employed by companies in the open-source software-development field, such as RedHat and EnterpriseDB.
Postgres is available on Linux, Windows and MacOS.


MySQL is another open-source RDBMS. It is a full-featured database system sponsored by Swedish company MySQL AB, which is now owned by Oracle after its parent company Sun Microsystems was bought out by Oracle in 2010.

MySQL is very popular for Web-based, back-end databases, either individually or as part of the Linux, Apache, MySQL, PHP (LAMP) stack used to deliver Web-centric applications.


Like SQL Server and Oracle DB, DB2 from IBM is a full-featured object RDBMS from a major player in the software industry. Originally developed in the early '80s exclusively for IBM’s mainframes, it was later ported to other platforms, such as Linux, Unix, Windows (LUW) and IBM’s own OS/2.

It is a widely used commercial RDBMS, and also has a small free version for developers called Express-C. In 2009, IBM released version 9.7 of DB2, which closely mimics the features of Oracle DB, the market leader. This has helped it capture some sales by making it easy for Oracle-savvy database professionals to easily understand and start working on DB2.

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Written by Dixon Kimani
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Dixon Kimani is an IT professional in Nairobi, Kenya. He specializes in IT project management and using technology to solve real-world business problems. He is also an avid freelance technical writer who specializes in IT and how to use technology to improve organizational efficiency. Full Bio