The Worlds of Database Systems

The Worlds of Database Systems

Databases today are necessary to each business. They are used to keep up internal records, to present data to customers and clients on the World-Wide-Web, and to support many other commercial processes. Databases are also found at the core of many scientific investigations. They represent the data gathered by astronomers, by investigators of the human genome, and by biochemists exploring the medicinal properties of proteins, along with many other scientists.

The power of databases comes from a body of knowledge and technology that has developed over several decades and is embodied in specialized software called a database enlargement system, or DBMS, or more colloquially a "database system". A DBMS is a powerful tool for creating and managing great amounts of data efficiently and allowing it to continue over long periods of time, securely. These systems are among the most difficult types of software available.

The capabilities that a DBMS offers the user are:

1.    Persistent storage. Like a file system, a DBMS supports the storage of very huge amounts of data that exists separately of any processes that are using the data. However, the DBMS goes far further than the file system in providing elasticity. Such as data structures that support resourceful access to very huge amounts of data.

2.    Programming interface. A DBMS allows the user or an application program to access and alter data through a powerful query language. Again, the benefit of a DBMS over a file system is the flexibility to control stored data in much more difficult ways than the reading and writing of files.

3.    Transaction management. A DBMS supports synchronized access to data, i.e.: simultaneous access by many distinctive processes (called "transactions") at once. To stay away from some of the unwanted consequences of simultaneous access, the DBMS supports separation, the appearance that transactions carry out one-at-a-time, and atomicity, the requisite that transactions execute either totally or not at all. A DBMS also supports stability, the ability to recover from failures or errors of many types.