Introduction to SQL.

Introduction:-SQL stands for structured query language.

AT that time we use database for storing the data which is very secure over the storing the data in file system. so for storing large amount of data we use databases.
for accessing the manipulating the data we use SQL.
SQL is the language by which we can easily access the data from the database and make changes in the data.
BY using the SQL we can create the tables ,insert the data,update the data,delete the data easily.
by using sql we can easily sort the values present in the tables.
Searching of data is done easily by SQL through select command.
Database reduces the redundancy of the data and maintains the integrity of the data.
WE can set permissions on tables.

Various Commands  present in SQL
1)DDL(Data Definition Language):-used to define database structure.

• Create 
• Alter 
• Drop
• Truncate 

2)DML(Data Manipulation Language):-used for managing data with in schema objects

• select
• update
• insert
• delete

3)DCL(Data Control Language):-

• Grant:-provide  privileges 
• Revoke:-withdraw privileges given by the GRANT 

4)TCL( Transaction Control Language):-statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.

• COMMIT - 
• SAVEPOINT - 
• ROLLBACK -
• SET TRANSACTION -