Database Introduction

Every organization has some information needs.An organization needs to save information about employees, departments and salaries. A library needs to keep a list of members, books , due dates, and fines. Suppose the regd.no, name, branch of a student is R001, Silan, Civil respectively. So R001, Silan, Civil are the information about a particular student. So these pieces of informations are known as data. An organization can keep data in various formats and different media like in a register, document in a filing cabinet, in a spreadsheets or in a database.

A database is an organized collection of information .

Suppose we want to know(retrieve) the branch of Silan, then we have to go through some process. By going through the process, we get data(branch of Silan) that is Civil, then that data is information.

Let's see another consideration, suppose a person want to know his balance in his account. Then he will go to ATM. In ATM he ll go through some process i.e insert the ATM card, go through some instructions followed by ATM machine, then after processing he ll know the available balance. That means data(balance) is stored in database. If we want to retrieve data from database, then by process we get data. So conclusionally we got the point,the processed data is called information.

Data processed information.

Let's start our study of relational database designing concepts with a fundamental question-"why do we need a Database".

The answer seems to be relatively simple and obvious. The common response is we need a database to store the data. If that is the case then why don't we use a word processor or spreadsheet because they are equally adept at storing data.

For that matter if storing data is the only purpose , then why not store it in a manual paper based register, why should we invest in a computer and a database software, both of which are costly investments, many of us will point out that we use computer because of faster processing speeds. But a simple fact needs to be understood- if storing data is the purpose , then typing the data into a computer will take roughly the same time as writing the data into a manual register that too a register will cost only Rs.25. so are we justified in using a computer-based database .
The answer seems to be no.

But then it is a fact that 80% of world wide computer resources and programming activities are devoted to database applications. It is also fact that today's IT enabled world depends on a computer databases for performing almost every processing activity. This means that the usage computer based database management systems is not at all unjustified. The fact is storing data is only a part of the entire range of operations performed by the DBMS. The more important is how quickly , easily, accurately, efficiently and reliably can the DBMS provide the right information at the right time , at the right place to the right person each and every time such information is required. This is power. This is what makes or breaks organizations.

So the correct answer is databases are used for providing information not just storing data.

Thus it is the most urgent requirement of all industries and companies irrespective of what area of operation they belong to.
That is why we need database.

So conclusionally we got the point the requirement of database is not storing data but more importantly to process that data and produce the required information accurately and then to make it available to the right person at the right time . if accurate information is not available to the right person at the right place at the right time , then the usage of databases is meaningless. Because today's world information is power.

DBMS(Database Management System)

• • To manage a database we need a DBMS(Database Management System). A DBMS is nothing but a software which helps us to manage a database.
• • Managing a database includes storing data into the database, retrieving data from the database, modifying the data in the database on request.
• • The main objective of a DBMS is to provide a way to store and retrieve database information that is both convenient and efficient.

What is RDBMS ?

• • RDBMS stands for Relational Database Management System.
• • RDBMS is an application which is managing Relational Database. Management includes inserting record into a table, deleting record from table, updating record in a table, retrieving record from table etc.
• • In current scenario many RDBMS product using in project developments like Oracle, MySQL, Microsoft SQL Server, and Microsoft Access etc.
• • RDBMS uses SQL queries to retrieve the data in the database.

What is a database table ?

• • In RDBMS context, a table is called as relation which is a collection of related data entries, and it consists of columns and rows.
• • A table is creating by taking attributes(columns).