Data Manipulation Language (DML)

What is DML? / List of operations that can be performed by Data Manipulation Language / DML examples / Types of DML / Procedural and Declarative DML

Data Manipulation Language (DML)

Data Manipulation is about handling the data stored in a database differently. The following operations would be considered as data manipulation in a database;

• Retrieving the data stored in the database – the way to view the data stored in the database

• Insertion of new data into the database – the way to insert and store the data in the database

• Deletion of stored data – the way to delete old or unwanted data from the database

• Modification of the stored data – the way to modify when required or when false data stored

The above said operations can be executed in Oracle using the following SQL statements respectively, for example;

Assume a table Teacher with attributes TID, Name, and Phone number. 

Retrieval – SELECT * FROM Teacher;

Insertion – INSERT INTO Teacher VALUES (100, ‘Ramesh’, 9900887771);

Deletion – DELETE FROM Teacher WHERE TID = 100;

Modification – UPDATE Teacher SET phone = 9900887766;

There are basically two types of DML languages;

1. Procedural DMLs – in procedural DMLs the user has to specify

• how to get the required data along with

• what data are required.

2. Declarative DMLs (Non-procedural) – it requires the user to specify

• Whatdata are required only. (Note:- The DML component of Structured Query Language (SQL) is declarative, ie., non-procedural)