Statements in SQL

There are five type of statements in SQL.

1. Data Definition Language (DDL).
2. Data Manipulation Language (DML).
3. Data Control Language (DCL).
4. Transaction Control Language (TCL).
5. Data Query Language(DQL). 

1.Data Definition Language - Create , Alter , Rename , Turncate , Drop.

2.Data Manipulation Language - Insert , Delete , Update.

3.Data Control Language - Grant , Revoke.

4.Trancation Control Language - Commit , Savepoint , Rollback.

5. Data Query Language - Select , Projection , Selection , Joins.

1.DDL (Data Definition Language) - 

    Create - Create command is use to create the table.

    Alter - Alter is use to perform the modification in the table.

    Rename - Rename is use to change the name of table.

    Syntax - rename old_tablename to new_tablename;

    Example - rename emp to employee; 

    Truncate - It is use to delete all the data of the table without affecting the table structure.

    If a table is truncated the data which is deleted can not be recovered.

    Syntax - truncate table table_name;

    Example - truncate table salgrade;

    Drop -Drop is use to delete table along withs all its data

    If table is drop is goes to recycle bin and it can be recover or restored.

     Syntax - Drop table table_name;

    Example - Drop table salgrade;

How to recover table with same name .

1.Table should be drop.

    Drop table

2.Flashback table table_name

    To befor drop;

    Example - flashback table salgrade

    to befor drop;

How to recover table with different name.

1.Table should be drop

    drop table

2.flashback table table_name

    To befor drop

    Rename to new_name;

How to delete table permanantly

1. Table should be drop.

2.When table is present in recycle bin we need to execute following command.

Syntax - purge table table_name;

Example - purge table salgrade;