What is the difference between data manipulation language and data definition language?

Answer 1

DDL or Data Definition Language is used to define the database and other related functions like creating tables, views, indexes etc. Some commands in DDL are:

• CREATE TABLE
• ALTER TABLE
• CREATE VIEW
• DROP TABLE
• etc.

DML or Data Manipulation Language is used to modify the contents of the data in a database. Ex:

• SELECT
• INSERT
• UPDATE
• DELETE
• ORDER BY
• GROUP BY
• etc.

DDL

Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:

• CREATE - to create objects in the database
• ALTER - alters the structure of the database
• DROP - delete objects from the database
• TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
• COMMENT - add comments to the data dictionary
• RENAME - rename an object

DML

Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples:

• SELECT - retrieve data from the a database
• INSERT - insert data into a table
• UPDATE - updates existing data within a table
• DELETE - deletes all records from a table, the space for the records remain
• MERGE - UPSERT operation (insert or update)
• CALL - call a PL/SQL or Java subprogram
• EXPLAIN PLAN - explain access path to data
• LOCK TABLE - control concurrency