Explain the basic concept of database management system.
Answers
Database Concepts
Database contains objects that are used for storing and managing information. To understand
a database in very simple language, let’s look at the example of your address book. What do
you store in an address book? You may have people’s name, people’s address, people’s phone
number and maybe even people’s birthdays. There is a common element here – people. In this
example, each person is considered an “item”. So, an item is what the database is storing
information about. When you were recording information in your address book, what did you ask
the people? What is your address? What is your phone number? etc. Each question that we ask
about our item is a “field”. Now, say you make new friends and want to add their information
to your address book. You will ask questions, get the answers and create a new “record”. So a
record is a set of information (made up of fields) stored in your database about one of the items. A
“value” is the actual text or numerical amount or date that you put in while adding information to
your database. When you put all the information together in a grid (like you do in a spreadsheet),
a collection of similar records creates a table.
A database can have one or many tables. An address book example is a very simple one, in real
life there are many more details involved. A big company would have in its database, one table for
its products, one table for its suppliers, one table for its customer details, one for orders received
and maybe many others. Basically each table in a database contains information about one type
of item. So a database is basically a container that holds tables and other objects and manages
how they can be used.
Another very important thing to remember is that when we put in information, we may have people
with the same name (there can be more than one Charu Arora) or the same address (members
of a family). But when creating a database an important feature is record uniqueness in every
table. It is important to be able to distinguish between different items having duplicate values.
Database Management System
A database management system is a software package with computer programs that controls the
creation, maintenance, and use of a database. It allows organizations to conveniently develop
databases for various applications. A database is an integrated collection of data records, files,
and other objects. A DBMS allows different user application programs to concurrently access the
same database.
Well knownDBMSs includeOracle,IBMDB2,MicrosoftSQLServer,MicrosoftAccess,PostgreSQL,
MySQL, FoxPro, and SQLite.
Data can be organized into two types:
• Flat File: Data is stored in a single table. Usually suitable for less amount of data.
• Relational: Data is stored in multiple tables and the tables are linked using a common field.
Relational is suitable for medium to large amount of data.