2.1 Database Management
System
Data
Data refers to the
collection of raw facts and figures that may or mayn’t give any sense. Eg: Ram,
16, years are data.
Information
Information is the
Processed or refined data that gives a complete sense. Information is an
organized collection of related data, which gives a complete sense. “Ram is a
student. He is 20 years old.”, is information that gives a complete sense.
Data Processing
The process of getting
useful information from data by processing data with the help of database
software is called data processing.
Database
Database is simply
organised collection of related data arranged in a specific order so that it
can be easily access, managed or updated. E.g. Flight schedule Dictionary,
Marks Ledger, Telephone Directory etc.
Advantage of database
Ø It allows sharing large
volume of data
Ø It allows searching of
data quickly
Ø It reduces data
duplication
Ø It allows advance
filtering of data
DBMS (Database
Management System)
DBMS is a software which
is used to store the data, process them and provide the useful information to
the user. It involves in creating, modifying, deleting and adding data in
database. Eg: Dbase, Fox Pro, Ms- Access, Oracle, Sybase, FoxBASE, SQL
DBMS is a software which helps to extract, view
and manipulate data in an organized way. In DBMS, data can be accessed, managed
and updated easily. E.g.: MS-Access, Oracle, Fox pro, Dbase etc.
Advantage of DBMS.
ž Reduce data redundancy
ž Control data
consistency: (anychange made in one file automatically done in all field)
ž Facilitates sharing of
data
ž Ensure data security
ž Maintain data integrity:
(make sure that database accept only the valid data)
Disadvantage of DBMS
ž Required H/W and S/W are
expensive.
ž Costly and
time-consuming procedures
ž High operating cost
ž Qualified persons are
required to operate.
ž Difficult to recover
backup
Computerized Database
a) It can store large
volume of data. It is very fast to find a specific record.
b) Data can be sorted into ascending or descending order on multiple criteria.
c) The database can be kept secure by use of passwords.
d) We can search data
very easily.
e) Modification is very
easy in comparison of manual database.
Non-Computerized
Database
a) It is limited by
physical storage available.
b) It can take a while to manually search through all of the records.
c) Difficult to sort data on more than one criteria.
d) The only security would be locking up the records.
Elements of Database
ž Field: Field is the
topic name under which records are stored. It is found in column wise. A column
in database is called field. For eg: Name, Age,Gender.
ž Record: A piece of
information under the related fields about any person, place, organization or
anything. For eg: Ram , 15, male.
ž Table: A table is
collection of records or group of
records. It contains no. of rows and columns.
ž Tuple: A record row in
database is called Tuple
Types of DBMS
•
RDBMS (Relational Database Management system)
•
ODBMS (Object-oriented Database Management system)
•
DDBMS (Distributed Database Management System)
•
HDBMS (Hierarchical
Database Management System)
RDBMS (Relational Database Management System)
RDBMS is a database management system that is based on the relation model
in which data is stored in the form of tables and the relationship among the
data is also stored in the form of tables.
E.g.: SQL, MS-Access, Oracle, etc.
MS-Access
MS-Access is a relational database management system developed by Microsoft
Corporation which is used to store and manipulates large volume of data in the
form of table.
Features of MS-Access
a) IT is simplest and most flexible DBMS solution today.
b) it is easy to search
and find the data.
c) Forms are used for viewing and editing the information.
d) Reports are used for summarizing and printing the data.
e) It provides the
flexible ways to add, edit, delete and display the related data.
f) Queries help to view,
change and analyses the data indifferent ways
Objects of MS-Access
a) Table
b) Form
c) Query
d) Report
e) Pages
f) Macro
g) Module
a) Table
A table is the primary
object of Ms-Access database. It is used to store data. A database may contain
one or more table. It is an object of MS-Access that stores large volume of
data in the form of rows and columns. The different ways to create table are:
i) Design view
ii) Using wizard
iii) Entering data
Importance of table
a) it is used to store the data.
b) Different properties
of a field can be set in a table.
c) It provides options for primary key which helps to make data consistent.
Record
Record is complete set of information. Record is a collection of multiple
related fields in a row which gives complete information about a person or
thing. E.g.: Khem Pokhara 1234567890
Field
Field is a small unit of information. A column in a table is called field, and
it contains a specific piece of information within a record. E.g.: Name,
Address, Telephone
b)
Query:
A query is an object of MS-access database which
is used to retrieve and display the records from a table or multiple tables
based on specified condition.
Importance of query.
Ø It is use to retrieve
and display the records of a table.
Ø It allow us to view,
change and analyze the data in various ways.
c)
Form:
Form
is an object of Ms-Access that provides a quick and easy way to insert and
modify records into our database.
Importance of form
Ø To allow users to
perform data entry.
Ø To edit, update or
delete the data.
Ø To provide a way
customize the presentation of data in the database.
d)
Report:
Report
is an object of MS-Access database that is used to organize and present the
data in an effective and understandable form.
Importance of report
Ø It is used to organize
and summarize the data in an effective
form.
Ø It present the data for
viewing online and printing.
e) Pages: used to enter or view
data from website or internet
f) Macros: small program to
automate repetitive task.
g) Modules: stores a programming
codes.