Why Different Database Management Systems?
In this section, you will find that there are at least three large Database Management System (DBMS) software products and one that is popular for smaller desktop or workgroup databases, which supports fewer users. Different DBMSs exist to fit the different needs of various companies and administrators. Each DBMS was created for its own particular purpose.You could say that they were designed to compete with one another, but that is not precisely true.They were each created to fit a particular set of database needs. Some were designed to be very fast, others were designed to be very easy to use, and still others were de-signed to operate almost seamlessly with the computer's operating system.
What Are Some Specific DBMS Software Products?
Some of the main products in the database world include Oracle, DB2, SQL Server, Access, and dBase. The following list contains a brief description of each of these systems. Following this list is discussion on why one system might be chosen over another:
Oracle-Oracle is a well-known, top-tier RDBMS. It is popular throughout the industry due to its speed, efficiency, and reliability. It runs on a variety of computer hardware and operating systems and is primarily used for larger database projects. Oracle is a rather expensive, but very complete, database environment. The specifics of Oracle are discussed in the "Oracle" section later in this article.
DB2-An RDBMS from IBM, DB2 is very comparable to Oracle in speed and can handle about the same workload. Like Oracle, it is expensive, high-maintenance software. Also like Oracle, it runs on a wide variety of computers under many operating systems. Because DB2 is another popular platform for "enterprise" (large-scale) databases, more information about DB2 is provided in the "DB2" section later in this article.
Microsoft SQL Server-The SQL Server RDBMS is Microsoft's enterprise-class database, which runs on Windows NT and Windows 2000. It is actually a relative of the Sybase database, which runs on Unix platforms. SQL Server has handled larger and larger databases with each new version of the product, but according to most analysts, it does not yet have the workload capacity of Oracle or DB2. Still, it is considered a price performance leader in the moderate-sized database category. SQL Server is also discussed in detail in the "SQL Server" section later in this article.
Microsoft Access-Access is Microsoft's smaller contribution to the database world. This program is geared more towards an office workgroup environment with fewer users (generally under a dozen, sometimes only one) than is typical of the databases listed previously, which often handle hundreds or thousands of users working with the database concurrently. Although Access does not have all of the fancy capabilities of larger databases, such as SQL Server, it also requires dramatically less administration than SQL Server does. Because many people migrate to SQL Server when their database "outgrows" Access, Microsoft has created a special tool called the "Upsizing Wizard" to assist in the conversion of Access databases to SQL Server.
dBase-dBase is a PC database platform that is no longer popular for new development. However, if you are involved with smaller database application systems, you might encounter it, if only when asked by someone to convert a dBase application to a newer or more scalable database. The dBase series of database programs (dBase II, III, IV, etc.) was very popular in the 1980s and early 1990s to implement smaller database application systems. It was so popular, in fact, that Microsoft acquired a very similar competing product called FoxPro, so as not to be left out of the dBase market.
Unlike more modern databases, dBase is a file-based rather than relational system. Most but not all database applications that access a dBase database are written in the relatively easy to understand but proprietary dBase programming language rather than a newer language like Visual Basic. Many organizations have run MS-DOS-based dBase systems for years on the grounds that "if it ain't broke, don't fix it." But the days of dBase systems depending on MS-DOS are numbered, as Microsoft advances its Windows platform. The ability to review an existing dBase database and convert its functionality to a modern database, such as Access or even SQL Server, has earned more than one database specialist the thanks of an organization and has helped launch many consulting careers.
Choosing Database Software
Which of the previously listed databases is the best to use or become familiar with? All of them, at least to a degree. When selecting a career in this area of IT, you have to realize that different clients and different companies require different databases. As a database designer or a database administrator, you may have to use more than one of these DBMSs in your environment.
How do you choose the right one for a particular project? Generally, it's easier than you might think because the choice usually isn't up to you. Many organizations (or departments within larger organizations) standardize on one particular vendor's database software, such as DB2, and perhaps even a particular well-tested version of that vendor's software. If your project's database can be force fit into the capabilities offered by that particular software, that's the platform on which it will be implemented. That may sound severe, but there is actually a great deal of sense behind it. For example, organizations employing very highly skilled database staff often want to utilize those skilled personnel in as many situations as possible. Although a particular database project might be more easily accomplished on Oracle than SQL Server, the company may have many internal SQL Server resources but no Oracle resources other than a consultant who is not available every hour of every business day. Similarly, the company may have invested a lot in tools to administer SQL Server databases and may have no tools that would allow easy administration of Oracle databases. In some cases, the choice of database may be up to the senior database manager or the company that is your client.