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