Introduction to DataBase Management System

(under construction....)

The Casual Definition: A database is a collection of related data which further joins to form meaningful information.

Implicit Properties of database are:

• it represent some aspect of real world, sometimes called mini-world or the universe of discourse.

• it is a logical coherent collection of data with some inherent meaning.

• it is designed, built and populated with data for a specific purpose.

• it has an intended group of users and some preconceived application in which these users are interested.

Database Management System (dbms): It is a collection of programs that enables user to create and maintain a database.

                                 The DBMS is a general purpose software system that facilitates the processes of defining, constructing, manipulating, and sharing database among various users and applications.

NOTES

• An application program accesses the database by sending queries or requests for data to dbms.
  
• A query typically, causes some data to be retrieved.
  
• A transaction may cause some data to be read and some data to be written into the database.
  
• Protection includes system protection against hardware or software malfunction (or  crashes) and security protection against unauthorized or malicious access.
  
• Maintenance A typical database may have a life cycle of many years, so dbms must maintain the database along with its contents by allowing system to evolve as requirement changes over time 

USES/ APPLICATIONS OF DBMS:

*Banking          *Airlines          *Universities          *Credit Card Transactions          *Telecommunication          *Finance          *Sales (record keeping)          *On-line retailers          *Manufacturing          *HR management

[user interfaces (UI/GUI) hide complexity and details of access to database in most cases]

The structure of data files is stored in the dbms catalog is separate from the access programs. This property is called as program-data independence. The information stored in catalog is called meta-data (data dictionary).