UNIT 1 – Ch1: Databases and Database Users
UNIT 1
Chapter 1: Databases and Database Users
1.1 INTRODUCTION
A database is a collection of related data. By data, we mean known facts that can be
recorded and that have implicit meaning. For example: names, telephone numbers, address
etc. A database has the following implicit properties.
▪ A database represents some aspects of the real world, sometimes called as mini-world
or the Universe of Discourse (UoD).
▪ A database is a logically coherent collection of data with some inherent meaning. A
random assortment of data cannot correctly be referred to as a database.
▪ A database is designed, built and populated with data for a specific purpose. It has an
intended group of users and some preconceived applications in which these users are
interested.
A database management system (DBMS) is a collection of programs that enables users
to create and maintain a database. The DBMS is a general-purpose software system that
facilitates the processes of defining, constructing, manipulating, and sharing databases
among various users and applications.
• Defining database involves specifying the data types, structures and constraints
for the data to be stored in the database.
• Constructing the database is the process of storing the data itself on some storage
medium that is controlled by the DBMS.
• Manipulating a database includes functions such as querying, updating and
generating reports on the data stored in the database.
• Sharing a database allows multiple users and programs to access the database
simultaneously.
An application program accesses the database by sending queries or requests for data
By Akshay
, UNIT 1 – Ch1: Databases and Database Users
to the 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.
DBMS also include protecting the database and maintaining it over a long period of time.
• Protection includes system protection against hardware or software malfunction
(or crashes) and security protection against unauthorized or malicious access.
• Maintaining the database system by allowing the system to evolve as
requirements change over time.
Figure 1.1 illustrates some of the concepts been discussed so far
1.2 CHARACTERISTICS OF THE DATABASE APPROACH
By Akshay
UNIT 1
Chapter 1: Databases and Database Users
1.1 INTRODUCTION
A database is a collection of related data. By data, we mean known facts that can be
recorded and that have implicit meaning. For example: names, telephone numbers, address
etc. A database has the following implicit properties.
▪ A database represents some aspects of the real world, sometimes called as mini-world
or the Universe of Discourse (UoD).
▪ A database is a logically coherent collection of data with some inherent meaning. A
random assortment of data cannot correctly be referred to as a database.
▪ A database is designed, built and populated with data for a specific purpose. It has an
intended group of users and some preconceived applications in which these users are
interested.
A database management system (DBMS) is a collection of programs that enables users
to create and maintain a database. The DBMS is a general-purpose software system that
facilitates the processes of defining, constructing, manipulating, and sharing databases
among various users and applications.
• Defining database involves specifying the data types, structures and constraints
for the data to be stored in the database.
• Constructing the database is the process of storing the data itself on some storage
medium that is controlled by the DBMS.
• Manipulating a database includes functions such as querying, updating and
generating reports on the data stored in the database.
• Sharing a database allows multiple users and programs to access the database
simultaneously.
An application program accesses the database by sending queries or requests for data
By Akshay
, UNIT 1 – Ch1: Databases and Database Users
to the 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.
DBMS also include protecting the database and maintaining it over a long period of time.
• Protection includes system protection against hardware or software malfunction
(or crashes) and security protection against unauthorized or malicious access.
• Maintaining the database system by allowing the system to evolve as
requirements change over time.
Figure 1.1 illustrates some of the concepts been discussed so far
1.2 CHARACTERISTICS OF THE DATABASE APPROACH
By Akshay
