Day 10: DBMS Basics

Hello Dear Students,
   Hope you all are doing good.....

So from now, we are going to cover the DBMS unit..

Let's get started from basics....

DATABASE MANAGEMENT SYSTEM(DBMS) 

Data is the raw facts means the facts which have not been processed. The processed form of the data is known as Information which is used for decision making basically. 

Database is the collection of data basically which is in an organized way and can be shared by multiple users but stored only once. The data is collected and stored in the Database. For example, the telephone directory where all the contacts are there in an alphabetical order(i.e. well organized), and can be access by multiple users on multiple times but store only once. In any organization, there is a lot of data about their customers, products, employees, etc. which needs to be stored in an organized way. So, there being database comes into existence. The database needs to be fully managed and controlled and the system by which it is done known as DataBase Management System(DBMS) as the very name suggests.

Features of Data in a Database-
  1. Data must be well organized.
  2. Data should be related.
  3. It should be correct.
  4. It should represent the data in the real world.
  5. It should be secure.
  6. Multiple access and stored once.
  7. Flexibility to change.
  8. It should be accessible.

Common Operations performed on the Database-
  1. Insertion - Adding new data to the Database.
  2. Deletion - Removing an existing data from the Database.
  3. Updation - Modifying/updating the existing data of the Database.
  4. Selection - Viewing/retrieving the stored data of the Database.

Various Applications of real world Database are
  • Banking systems
  • ATM machines(Automated Teller Machines)
  • Flight Reservation Systems
  • Computerized Library Systems
  • Super Markets
  • Credit Card
  • Railway reservation systems
  • Insurances
  • Stock Trading Systems, and so on...
Every field where there is need to collect the data is the application of database.


Basic Components of the Database Systems -
  • DATA - The data is the major component in the database system as the database itself is a collection of data. Data can be- User Data, Meta Data, Application Metadata. Metadata is the data about data which describes the properties and context of data. Application Metadata stores the queries, reports, etc.
  • HARDWARE - For DBMS to run, the hardware is required. The hardware consists of- secondary storage devices(magnetic disks, CD-ROM, magnetic tapes, etc.), Input/Output Devices(mouse, keyboard, etc.) , processors, main memory and so on.
  • SOFTWARE - The software consists of DBMS such as Oracle, MS-Access, MYSQL Server, Sybase, Foxpro, Dbase, DB2, and so on. and the Operating Systems such as Unix, Linux, Mac OS, and so on.
  • USERS - Users are the persons who access the database, Users can be- DBA(DataBase Administrator) , Database designers, End Users, or Application Programmers.


DBMS - DBMS stands for Data Base Management System. It is basically the software which is used to manage the Database. DBMS acts as a mediator between users and the database. 

Functions performed by DBMS -
  1.  It provides the data storage management and data dictionary management
  2. User security and data privacy
  3. Integrity of the database
  4. Provides data recovery and backups
  5. Minimizes data consistency
  6. Easy to understand and use the queries
Commercially available DBMS -
  • For small organizations- MS-Access, File Maker Pro, Superbase, etc..
  • For client/server enterprises- Oracle, SQL Server, DB2, Informix, Paradox, etc..


DATABASE LANGUAGES - The database languages are basically of 3 types -
  • DDL - DDL stands for Data Definition Language. This is basically used to define various types of data in the database. It cannot be used to perform any manipulations on the data. The various DDL commands are- 
  1. CREATE
  2. ALTER
  3. DROP
  4. RENAME
  5. TRUNCATE
  6. COMMENT

  • DML - DML stands for Data Manipulation Language. It performs various manipulations on the data.The various DML commands are-
  1. SELECT
  2. UPDATE
  3. INSERT
  4. DELETE
  5. MERGE
  6. CALL
  7. EXPLAIN PLAN
  8. LOCK TABLE

  • DCL - DCL stands for Data Control Language. It is basically used to control/access the data in the database. The DCL commands are-
  1. GRANT
  2. REVOKE

  • TCL - TCL stands for Transaction Control Language. It is basically used to control the behavior of transactions on the data. The TCL commands are-
  1. COMMIT
  2. ROLLBACK
  3. SAVEPOINT
  4. SET TRANSACTION


Best of Luck Students,
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