SQL Tutorial 
                                                                              
                                                                                 
         
        SQL TUTORIAL 
        Simply Easy Learning by tutorialspoint.com 
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                           ABOUT THE TUTORIAL 
                                      SQL Tutorial 
               SQL is a database computer language designed for the retrieval and management of data in relational 
               database. SQL stands for Structured Query Language. 
               This tutorial will give you quick start with SQL. 
                                        Audience 
               This reference has been prepared for the beginners to help them understand the basic to advanced 
               concepts related to SQL languages. 
                                      Prerequisites 
               Before you start doing practice with various types of examples given in this reference, I'm making an 
               assumption  that  you  are  already  aware  about  what  is  database,  especially  RDBMS  and  what  is  a 
               computer programming language. 
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               TUTORIALS POINT 
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                                   Table of Content 
               SQL Tutorial ............................................................................. 2 
               Audience .................................................................................. 2 
               Prerequisites ............................................................................ 2 
               Copyright & Disclaimer Notice .................................................. 2 
               SQL Overview ........................................................................ 15 
               What is SQL? ........................................................................................... 15 
               Why SQL? ................................................................................................ 15 
               History: ..................................................................................................... 16 
               SQL Process: ........................................................................................... 16 
               SQL Commands: ...................................................................................... 17 
               DDL - Data Definition Language: ............................................................. 17 
               DML - Data Manipulation Language: ........................................................ 17 
               DCL - Data Control Language: ................................................................. 17 
               DQL - Data Query Language: .................................................................. 17 
               SQL RDBMS Concepts .......................................................... 18 
               What is field? ............................................................................................ 19 
               What is record, or row? ............................................................................ 19 
               What is column? ....................................................................................... 19 
               What is NULL value?................................................................................ 19 
               SQL Constraints: ...................................................................................... 20 
               NOT NULL Constraint: ............................................................................. 20 
               DEFAULT Constraint:............................................................................... 21 
               Example: .................................................................................................. 21 
               Drop Default Constraint: ........................................................................... 21 
               UNIQUE Constraint: ................................................................................. 21 
               Example: .................................................................................................. 21 
               DROP a UNIQUE Constraint: ................................................................... 22 
               PRIMARY Key: ......................................................................................... 22 
               Create Primary Key: ................................................................................. 22 
               Delete Primary Key: ................................................................................. 23 
               FOREIGN Key: ......................................................................................... 24 
               Example: .................................................................................................. 24 
               DROP a FOREIGN KEY Constraint: ........................................................ 25 
               CHECK Constraint: .................................................................................. 25 
               Example: .................................................................................................. 25 
               DROP a CHECK Constraint: .................................................................... 25 
               INDEX: ..................................................................................................... 26 
               TUTORIALS POINT 
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