what is DDL and DML in SQL

[mouse]

I have been using SQL for quite some time but someone asked me about DDL and DML. what are they, are the some kind of commands? Could you please explain me about it?

[getpfunky]

So you have been using SQL for quite some time. But I think you dont know much about it. dont worry,

Data Manipulation Language (DML)
SQL is a syntax for executing queries. But the SQL language also includes a syntax to update, insert, and delete records. These query and update commands together form the Data Manipulation Language (DML) which are a part of SQL part of SQL:

* SELECT command is used to extract data from a database table
* UPDATE command updates data in a database table
* DELETE is used to delete data from a database table
* INSERT INTO inserts new data into a database table



SQL Data Definition Language (DDL):
The Data Definition Language (DDL)is a part of SQL that allows the user to create or delete the database tables. We can also define indexes (keys), specify links between tables, and impose constraints between database tables.
The most important DDL statements in SQL are:

* CREATE TABLE - creates a new database table
* ALTER TABLE - alters (changes) a database table
* DROP TABLE - deletes a database table
* CREATE INDEX - creates an index (search key)
* DROP INDEX - deletes an index