Define DDL and DML

Answer 1

SQL

These are the main categories are

DDL(Data Definition Language)

DML ( Data Manipulation Language)

DQL( Data Query Language)

DCL( Data control Language)

Data administration commands

Transactional control command.

ddl includes insert ,delete ,update values

it include select statements,

it include insert statement,

it includes drop statements

Answer 2

DDL means - Data Definition Language, which helps in defining the structure of the database, alter its structure and also data types of the data elements. This will not deal with the data values(data items) or the records inserted in the database.

DML means - Data Manipulation Language, which helps in dealing with making the changes to the records present in the database.

Answer 3

DDL:- Data Definition Language. It is a set of SQL commands used to create, modify & delete database structure or schema. e.g.

*create:- used to create object in database.

*alter:- used to alter or change the structure of database.

*drop:- used for deleting the objects from database.

*truncate:- used to remove all records from the database.

*comment:- add comment to data dictionary.

*rename:- used for renaming an object.

DML:- Data manipulation language. It is used for managing data within schama objects.It allows changing data within the database. e.g.

*select:- used to retrieve data from database

*insert:- used to add record into the table

*update:- used to update or change the data within the database.

*delete:-used to delete all record from a table, the space for record remains.

*merge:- used to upsert operation(upsert means insert or update)

*call:- used to call a PL/SQL or java subprogram.

*explain plan:- used to explain access path to data.

*lock table:- it is used to control the concurrency.

DCL:- Data control language. that control access to data & to the database.Occassionaly DCL statements are grouped with DML statements. e.g.

*grant:- it is used to give user's access rights to the database.

* revoke:- it is used to withdraw access rights given with the grant command.

DQL:- Data Query Language.It allows getting data from the database & impossing ordering upon it. It includes select statements.