A dedicated server used to run a database intensive application(s) is usually called dedicated database hosting server. The sever may run a whole website as well as the database or may be used just for a database. Servers that are used for database intense programs will have more ram than a typical server.
You may want to consider a database host if you use database intensive programs such as CRM or ERP. The servers used for database hosting have more memory. Database servers do not need to be used just for hosting databases. They are a specific type of dedicated server that is designed to maximize the performance of databases. The servers will have a large memory. Running the database will be the top priority over any other applications.
Database servers can hold 100s of Megs or even Gigs of information in tables. By using a simple command, in as little as a tenth of a second, you can find information you need from the website in less than a second. For example, if you have a database with names and other personal data, you can run a search to find all the last names beginning with K. Google tries to keep search results below a half of a second. This is really fast considering their database contains over three trillion web pages.
By having more RAM data from the databases can be accessed quickly. Data can be retrieved from RAM about 10 times faster, than from the hard drive. Therefore some data from a database will be stored in the RAM. The greater the amount of RAM a server has, the faster information can be retrieved from the database.
The majority of websites will not require dedicated database hosting. Even if you have an Ecommerce website, you probably just need a hosting plan that includes database access. If a database is the most important part of an application, then you may need dedicated database hosting.
As with any dedicated server, there is a good deal of work involved to manage and maintain the servers. Much of the time will be spent on database administrative tasks. If you do not have the knowledge you need or if you do not have anyone on your staff, which does, you may wish to consider managed hosting. The hosting provider will then do some of the security and maintenance tasks for you. Some hosting companies will also offer other services for an additional fee. The services may include tasks in addition to maintaining the servers. They may also optimize the tables and make sure they are setup for fast search results.
For the average website, dedicated database hosting is not necessary. Even if your website will utilize some database applications, you can usually use hosting plans that include database capabilities. However if your website has intensive database applications, you may wish to consider dedicated database hosting for optimal database performance.