Database environment can be classified into three simple categories:
Database Administrator - They are responsible to monitor and maintain the databases in an organization.
Systems Developers - They are responsible for the development of the computer applications which will talk to the database in do the necessary operations and display the results to the end users.
User Interface - This is how the computer application looks and what the end user will use to interact.
Application Programs- This is the core of the computer application. These are the programs which are related to the application, so that user can use the system to get output .
Repository- It is a centralized knowledge base . It contains all the data definitions , report format and definitions of organizations which are related and system components.
Database Management System- It is a commercial software system which is used to create , maintain and provide controlled access to the repository.
Database - It is a collection of logically related data which is required to meet the needs of applications or users of organizations.
SQL is a special purpose programming language designed for managing data held in relational database management systems(RDBMS). 
1. SQL Components:
There are three components.
a. Data Definition Language .
b. Data Manipulation Language .
c. Data Control Language .
Data Definition Language (DDL):
This component is used to CREATE and ALTER (or) modify the tables and the objects of that database.
CREATE TABLE 'TABLENAME' , DROP TABLE 'TABLENAME' and ALTER TABLE 'TABLENAME' are the main commands which come under the category of DDL.
Definition of any object is stored in Data Dictionary by using CREATE command and is deleted from Data Dictionary only if DROP command is used or else it remains there permanently.
Data Manipulation Language (DML):
This component is used to manipulate the data within the tables present in the database .
SELECT, INSERT, UPDATE and DELETE are main DML related operations . Using the commands the data in the tables present as rows and columns can be manipulated.
Data Control Language (DCL):
This component is used to create privileges to users for access to data or to revoke them from manipulating the data .
GRANT and REVOKE are the main DCL related operations, which will result in granting the users privilege to access the data and REVOKE command to revoke user privileges based on the requirement and rules of access (which is defined by the organization or administrator) .
2. SQL Structure:
The basic relational model structure consists of tables with rows and columns.
These tables are given names and data related to them are maintained respectively.
The sequence of steps when a new Database is created and to make it relational: