SQL Statements

Introduction : 
Guys, here we will learn about SQL statements, types and role.

Types of SQL Statements :
SQL statements mainly categorized into following kinds.

• DDL (Data Definition Language)
• DML (Data Manipulation Language)
• DQL (Data Query Language)
• DCL (Data Control Language)
• TCC (Transaction Control Commands)

1. Data Definition Language : 
In DDL, there are three types of statements.
(i) CREATE - is used to create database, table, index , view etc.

(ii) ALTER - is used to modify database, table, index , view etc.

(iii) DROP - is used to delete the schema of database, table, index , view etc.

2. Data Manipulation Language :

In DML, there are three types of statements.
(i) INSERT - is used to insert row(s) in a database, table

(ii) UPDATE - is used to change(update) row(s) in a database.

(iii) DELETE - is used to delete row(s) from a database.

3. Data Control Language :

In DCL, there is only one statement.
(i) SELECT - is used to select/retrieve row(s) from a database

4. Data Query Language : In DQL, there is following statements.
(i) GRANT - is used to give/set the privileges to the user 

(ii) INVOKE - is used to withdraw the privileges given by GRANT

5. Transaction Control Language/Commands : In TCL, there are four types of statements.
(i) COMMIT - permanently saves database transactions (will not be ROLLBACK)
(ii) ROLLBACK - undoes database transactions

(iii) SAVEPOINT - creates points within groups of transactions in which to ROLLBACK 

(iv) SET TRANSACTION - places a name on transaction