Relational Database Management Systems
Content
Relational Database Management Systems
RDBMS
Data:
Facts which does nat have any meaning. But it will play a crucial role. Database: A database is a collection of interrelated data.
Database management System( DBMS ) A DBMS is a collection of programs that enables users to create and maintain a database. The DBMS is hence a general purpose system software that facilitates the process of defining, constructing and manipulating databases for various applications.
DBMS
Defining
involves specifying the data types , structures and constraints for the data to be stored in the database.
Constructing
is the process of storing the data itself on some storage medium that is controlled by the DBMS.
Manipulating
includes functions such as querying the database, updating the database and generating reports.
Traditional Approach
File System is the traditional method of data storage. Types of files used: A master file:
Stores relatively static data about an entity. Changes rarely.
A Transaction file:
Stores relatively transient data. Changes frequently.
Disadvantages of traditional approach
Data security. Data redundancy. Data isolation Program/Data dependence Lack of flexibility Concurrent access anomolies.
Advantages Of DBMS
Data independence Data Sharing. Allows concurrent access to the databases. Controls redundancy and inconsistency. Provides security. Enforces integrity(by preventing the entry of invalid information). Enables backup and recovery from system crash.
Types of Database
Centralized Database:
• All data is located at a single site.
Distributed Database
The database is stored on several computers.
RDBMS
Data:
Facts which does nat have any meaning. But it will play a crucial role. Database: A database is a collection of interrelated data.
Database management System( DBMS ) A DBMS is a collection of programs that enables users to create and maintain a database. The DBMS is hence a general purpose system software that facilitates the process of defining, constructing and manipulating databases for various applications.
DBMS
Defining
involves specifying the data types , structures and constraints for the data to be stored in the database.
Constructing
is the process of storing the data itself on some storage medium that is controlled by the DBMS.
Manipulating
includes functions such as querying the database, updating the database and generating reports.
Traditional Approach
File System is the traditional method of data storage. Types of files used: A master file:
Stores relatively static data about an entity. Changes rarely.
A Transaction file:
Stores relatively transient data. Changes frequently.
Disadvantages of traditional approach
Data security. Data redundancy. Data isolation Program/Data dependence Lack of flexibility Concurrent access anomolies.
Advantages Of DBMS
Data independence Data Sharing. Allows concurrent access to the databases. Controls redundancy and inconsistency. Provides security. Enforces integrity(by preventing the entry of invalid information). Enables backup and recovery from system crash.
Types of Database
Centralized Database:
• All data is located at a single site.
Distributed Database
The database is stored on several computers.
