Sequential Query Language (SQL) Servers are database servers. While there are database servers that do not utilize SQL to perform queries against a database, these are generally proprietary and non-robust implementations. SQL is as ubiquitous to database servers as HTML is to websites. When one begins to look for a database server there are several major options:

• Microsoft SQL Server 2008 R2 – Microsoft has created a long-line of enterprise level, reliable SQL servers. These include there 7.0 and 2000 versions. The current version is 2008 R2. A lite version that is freely available is called SQL Server Express, the successor to MSDE. SQL Server 2008 R2 is used by many large enterprises as well as small businesses.
• MySQL – MySQL is a popular free/open source implementation. It has also taken rapid bounds forward and serves as the back-end for numerous large internet companies. It is especially popular amongst adherents to an open source model (e.g. LAMP in which M stands for MySQL).
• Other options include Oracle and PostgreSQL, but neither of these is nearly as popular as either SQL Server from Microsoft or MySQL.

Backing up SQL Databases:

• Every database should be backed up regularly, and generally apart from being backed up as a whole system. This is mainly because of the difficulties inherent in backing up software such as SQL databases which are in constant flux. Microsoft offers some built-in tools for backups but these are somewhat simplistic and much better options are available, especially if you have any sizeable amount of data to backup (e.g. a 15 GB or larger database).
• Three companies that offer advanaced database backup tools for Microsoft SQL Server are Red-Gate, Idera, and Quest. My personal favorite is Red-Gate. Their software is simple, works well, and the price point is significantly lower than their competitors. You can get an entry level Red-Gate SQL Backup Lite application from them for $149.