1. INTRODUCTION TO DATABASE
TOPICS TO LEARN
1.OVERVIEW
2.INTRO
3.OPERATION ON FILE
4.INTRO TO DATABASE
1.OVERVIEW
In this chapter we will study concept of data,files and then different
operations that we can perform on the file.Data is collection of facts,such as values or
measurements.It can numbers,words,measurement,observation or even just description
of things.
After understanding data and files we will study
DATABASE.database is also a type of data storage like file but it has some higher
facilities and features than a regular file which help us to manage the data easily.
2.INTRODUCTION
DATA :-
In general we define data as ; it is information in row unorganized
form(such as word ,numbers or symbols) that represent conditions,ideas, or objects.
In short ,data is collection of facts,figure and statistics related to an objects.Data can be
processed to create useful info.Hence we can say manipulated and processed form of
data is called information,which is more meaningful than data.Data is used as input for
processing and information is the output of this processing .
• In term of computer data are symbols or signals that are input to the
computer,stored in computer, and processed by a computer for output as usable
information.
• We can say for example: 011000110011... can be presented as binary data in
computer.
• Data is often distinguish from program in computer.we define a program, as a set
of instruction that perform a particular task for computer.
FILES :- We can use the file to save data.In general we keep our document in a
folder file where they can be safe and secured.
• In term of computer we define a file as a collection of bytes stored as an
individual entity.all data in disk are stored as a file with an assigned filename that
is unique within a directory it resides in.
• Almost all info stored in computer must be in file.for example,program file stored
program.
• To the computer a file is nothing more than a series of bytes.
• The software that manipulates it knows the structure of file.
2. 3.OPERATION ON FILE
Two types of operation on file--
1. RETRIEVAL OPERATION
2. UPDATE OPERATION
When we want to extract the data from file for reading purpose then we
perform retrieval operation on the file.Retrieval operation do not change the content of
file;t only locates the records in file.
Update operation on other hand ;change the file by modifying the
records,deleting the records and inserting new records.That we actually modify the
content in file in update opertaion.
4.INTRODUCTION TO DATABASE
DEFINATION:--
• DBMS provide us another type of file to store image type of data in computer.
• A database is an application that manages data and allow fast storage and
retrieval of that data.A database can organized ,store,and retrieve large amount
of data easily.
• And a DBMS is a piece of software that is designed to make different database
operations easily.
• To maintain large amount of data in conventional file system is a time consuming
and more critical job and we probably do not have 30GB of main memory to hold
all the data.
• Hence we can deal with this data management problem by storing the data in a
database.
• there are different types of database but the most popular is a relational
database that store data in tables where each row in the table hold the same sort
of information.In early 1970's Ted Codd, an IBM reasercher devised 12 laws of
normalization .
4.1 COMPONENT OF DATABASE
A database consist of four elements.
DATA ITEMS
Each attributes of an entity is represented in storage by a data items.
Foe example: Suppose there is a database of "customer account".And this database
contains attributes Cust_name,Cust_id,Cust_add,Balance.
2.RELATIONSHIP
It represent a correspondence between the various data element/entities.
3.CONSTRAINS
We can say that the Constrains within a database are rules,which control values allowed
in column and also enforce the integrity between columns and tables.
4.SCHEMA
3. It described the organization of data and relationship between the database.In short
schema is a logical structure of database.
