Summary Introduction of DBMS (Database Management System

Introduction of DBMS (Database Management
System) – Set 1

A Database Management System (DBMS) is a software system that is designed to
manage and organize data in a structured manner. It allows users to create, modify, and
query a database, as well as manage the security and access controls for that database.
DBMS provides an environment to store and retrieve the data in coinvent and efficient
manner.
Key Features of DBMS
 Data modeling: A DBMS provides tools for creating and modifying data models,
which define the structure and relationships of the data in a database.
 Data storage and retrieval: A DBMS is responsible for storing and retrieving data
from the database, and can provide various methods for searching and querying the
data.
 Concurrency control: A DBMS provides mechanisms for controlling concurrent
access to the database, to ensure that multiple users can access the data without
conflicting with each other.
 Data integrity and security: A DBMS provides tools for enforcing data integrity and
security constraints, such as constraints on the values of data and access controls that
restrict who can access the data.
 Backup and recovery: A DBMS provides mechanisms for backing up and
recovering the data in the event of a system failure.
 DBMS can be classified into two types: Relational Database Management System
(RDBMS) and Non-Relational Database Management System (NoSQL or Non-SQL)
 RDBMS: Data is organized in the form of tables and each table has a set of rows and
columns. The data are related to each other through primary and foreign keys.
 NoSQL: Data is organized in the form of key-value pairs, documents, graphs, or
column-based. These are designed to handle large-scale, high-performance scenarios.
A database is a collection of interrelated data which helps in the efficient retrieval,
insertion, and deletion of data from the database and organizes the data in the form of
tables, views, schemas, reports, etc. For Example, a university database organizes the
data about students, faculty, admin staff, etc. which helps in the efficient retrieval,
insertion, and deletion of data from it.
Database Languages
 Data Definition Language
 Data Manipulation Language
 Data Control Language
 Transactional Control Language
Data Definition Language

, DDL is the short name for Data Definition Language, which deals with database schemas
and descriptions, of how the data should reside in the database.

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 CREATE: to create a database and its objects like (table, index, views, store
procedure, function, and triggers)
 ALTER: alters the structure of the existing database
 DROP: delete objects from the database
 TRUNCATE: remove all records from a table, including all spaces allocated for the
records are removed
 COMMENT: add comments to the data dictionary
 RENAME: rename an object
Data Manipulation Language
DML is the short name for Data Manipulation Language which deals with data
manipulation and includes most common SQL statements such SELECT, INSERT,
UPDATE, DELETE, etc., and it is used to store, modify, retrieve, delete and update data
in a database.
 SELECT: retrieve data from a database
 INSERT: insert data into a table
 UPDATE: updates existing data within a table
 DELETE: Delete all records from a database table
 MERGE: UPSERT operation (insert or update)
 CALL: call a PL/SQL or Java subprogram
 EXPLAIN PLAN: interpretation of the data access path
 LOCK TABLE: concurrency Control

Data Control Language
DCL is short for Data Control Language which acts as an access specifier to the
database.(basically to grant and revoke permissions to users in the database
 GRANT: grant permissions to the user for running DML(SELECT, INSERT,
DELETE,…) commands on the table
 REVOKE: revoke permissions to the user for running DML(SELECT, INSERT,
DELETE,…) command on the specified table
Transactional Control Language
TCL is short for Transactional Control Language which acts as an manager for all types
of transactional data and all transactions. Some of the command of TCL are
 Roll Back: Used to cancel or Undo changes made in the database
 Commit: It is used to apply or save changes in the database
 Save Point: It is used to save the data on the temporary basis in the database
Data retrieval language: