SQL and the Evolution of Database Management

One of the major tasks of a computer system is to store and manage data. To handle this task, specialized computer programs known as database management systems began to appear in the late 1960s and early 1970s. A database management system, or DBMS, helped computer users to organize and structure their data and allowed the computer system to play a more active role in managing the data. Although database management systems were first developed on large mainframe systems, their popularity quickly spread to minicomputers, and then to computer workstations, personal computers, and specialized server computers.

Database management has also played a key role in the explosion of computer networking and the Internet. Early database systems ran on large, monolithic computer systems, where the data, the database management software, and the users or application programs accessing the database all operated on the same system. The 1980s and 1990s saw the explosion of a new client/server model for database access, in which a user or an application program running on a personal computer accesses a database on a separate computer system by using a network. In the late 1990s, the increasing popularity of the Internet and the World Wide Web impacted the architecture of data management again. Today, users require little more than a web browser to access and interact with databases, not only within their own organizations, but also around the world. These Internet-based architectures usually involve three or more computer systems—one that runs the web browser and interacts with the user, connected over the Internet to a second system that runs an application program or application server, which is in turn connected to a third system that runs the database management system.

Database management has become a very big business. Independent software companies and computer vendors ship billions of dollars’ worth of database management products every year. Virtually all enterprise-class computer applications that support the daily operation of large companies and other organizations use databases. These applications include some of the fastest-growing application categories, such as Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), Supply Chain Management (SCM), Sales Force Automation (SFA), and financial applications. Specialized high-performance server computers optimized to run the most popular database software constitute a multibillion-dollar market, and low-cost servers used exclusively for data management add billions more. Databases provide the intelligence behind most transaction-oriented web sites, and they are used to capture and analyze user interactions with web sites. Database management thus touches every segment of the computer market.

Since the late 1980s, a specific type of DBMS, called a relational database management system (RDBMS), has become so popular that it is the standard database form. Relational databases organize data in a simple, tabular form and provide many advantages over earlier types of databases. SQL is specifically a relational database language used to work with relational databases.

Source of Information : MCGraw Hill - SQL the Complete Reference 3rd Edition (10-2009)


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