Short Notes: Database Concepts | Computer Science for Grade 12 PDF Download

 Page 1


DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated.
In Database ,Data is organized into rows, columns and tables,
and it is indexed to make it easier to find relevant
information. It works like a container which contains the
various object like Tables, Queries, Reports etc. in organized
way.
Page 2


DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated.
In Database ,Data is organized into rows, columns and tables,
and it is indexed to make it easier to find relevant
information. It works like a container which contains the
various object like Tables, Queries, Reports etc. in organized
way.
WHY DO WE NEED DATABASE
? To manage large chunks of data: if size of data increases into
thousands of records, it will simply create a problem to
manage.Database can manage large amount of data.
? Accuracy: Through validation rule in database ,data accuracy can
be maintained.
? Ease of updating data: With the database, we can flexibly update
the data according to our convenience. Moreover, multiple
people can also edit data at same time.
? Security of data: With databases we have security groups and
privileges to restrict access.
? Data integrity: In databases, we can be assured of accuracy and
consistency of data due to the built in integrity checks and access
controls.
DATABASE CONCEPTS
Page 3


DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated.
In Database ,Data is organized into rows, columns and tables,
and it is indexed to make it easier to find relevant
information. It works like a container which contains the
various object like Tables, Queries, Reports etc. in organized
way.
WHY DO WE NEED DATABASE
? To manage large chunks of data: if size of data increases into
thousands of records, it will simply create a problem to
manage.Database can manage large amount of data.
? Accuracy: Through validation rule in database ,data accuracy can
be maintained.
? Ease of updating data: With the database, we can flexibly update
the data according to our convenience. Moreover, multiple
people can also edit data at same time.
? Security of data: With databases we have security groups and
privileges to restrict access.
? Data integrity: In databases, we can be assured of accuracy and
consistency of data due to the built in integrity checks and access
controls.
DATABASE CONCEPTS
Database Management System(DBMS)
? A DBMS refers to a software that is responsible for storing,
maintaining and utilizing database in an efficient way.
? A Database along with DBMS software is called Database
System.
? Example of DBMS software are Oracle, MS SQL Server, MS
Access, Paradox, DB2 and MySQL etc.
? MySQL is open source and freeware DBMS.
DATABASE CONCEPTS
Page 4


DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated.
In Database ,Data is organized into rows, columns and tables,
and it is indexed to make it easier to find relevant
information. It works like a container which contains the
various object like Tables, Queries, Reports etc. in organized
way.
WHY DO WE NEED DATABASE
? To manage large chunks of data: if size of data increases into
thousands of records, it will simply create a problem to
manage.Database can manage large amount of data.
? Accuracy: Through validation rule in database ,data accuracy can
be maintained.
? Ease of updating data: With the database, we can flexibly update
the data according to our convenience. Moreover, multiple
people can also edit data at same time.
? Security of data: With databases we have security groups and
privileges to restrict access.
? Data integrity: In databases, we can be assured of accuracy and
consistency of data due to the built in integrity checks and access
controls.
DATABASE CONCEPTS
Database Management System(DBMS)
? A DBMS refers to a software that is responsible for storing,
maintaining and utilizing database in an efficient way.
? A Database along with DBMS software is called Database
System.
? Example of DBMS software are Oracle, MS SQL Server, MS
Access, Paradox, DB2 and MySQL etc.
? MySQL is open source and freeware DBMS.
DATABASE CONCEPTS
Advantages of Database System
? Databases reduces Redundancy
It removes duplication of data because data are kept at one place and all the
application refers to the centrally maintained database.
? Database controls Inconsistency
When two copies of the same data do not agree to each other, then it is called
Inconsistency. By controlling redundancy, the inconsistency is also controlled.
? Database facilitate Sharing of Data
Data stored in the database can be shared among several users.
? Database ensures Security
Data are protected against accidental or intentional disclosure to unauthorized
person or unauthorized modification.
? Database maintains Integrity
It enforces certain integrity rules to insure the validity or correctness of data. For
ex. A date c an’ t be like 31/31/2000.
DATABASE CONCEPTS
Page 5


DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated.
In Database ,Data is organized into rows, columns and tables,
and it is indexed to make it easier to find relevant
information. It works like a container which contains the
various object like Tables, Queries, Reports etc. in organized
way.
WHY DO WE NEED DATABASE
? To manage large chunks of data: if size of data increases into
thousands of records, it will simply create a problem to
manage.Database can manage large amount of data.
? Accuracy: Through validation rule in database ,data accuracy can
be maintained.
? Ease of updating data: With the database, we can flexibly update
the data according to our convenience. Moreover, multiple
people can also edit data at same time.
? Security of data: With databases we have security groups and
privileges to restrict access.
? Data integrity: In databases, we can be assured of accuracy and
consistency of data due to the built in integrity checks and access
controls.
DATABASE CONCEPTS
Database Management System(DBMS)
? A DBMS refers to a software that is responsible for storing,
maintaining and utilizing database in an efficient way.
? A Database along with DBMS software is called Database
System.
? Example of DBMS software are Oracle, MS SQL Server, MS
Access, Paradox, DB2 and MySQL etc.
? MySQL is open source and freeware DBMS.
DATABASE CONCEPTS
Advantages of Database System
? Databases reduces Redundancy
It removes duplication of data because data are kept at one place and all the
application refers to the centrally maintained database.
? Database controls Inconsistency
When two copies of the same data do not agree to each other, then it is called
Inconsistency. By controlling redundancy, the inconsistency is also controlled.
? Database facilitate Sharing of Data
Data stored in the database can be shared among several users.
? Database ensures Security
Data are protected against accidental or intentional disclosure to unauthorized
person or unauthorized modification.
? Database maintains Integrity
It enforces certain integrity rules to insure the validity or correctness of data. For
ex. A date c an’ t be like 31/31/2000.
DATABASE CONCEPTS
Data Model- Way of data representation
Data model is a model or presentation which shows How data is organized ? or stored
in the database. A data is modeled by one of
the following given-
? Relational Data Model
In this model data is organized into Relations or Tables (i.e. Rows and Columns). A row
in a table represents a relationship of data to each other and also called a Tuple or
Record. A column is called
Attribute or Field.
? Network Data Model
In this model, data is represented by collection of records and relationship among data
is shown by Links.
? Hierarchical Data Model
In this model, Records are organized as Trees. Records at top level is called Root record
and this may contains multiple directly linked
children records.
? Object Oriented Data Model
In this model, records are represented as a objects. The collection of similar types of
object is called class.
DATABASE CONCEPTS