DML Commands Overview

Introduction

DML (Data Manipulation Language) commands are used to manipulate data in the database. They allow you to insert, update, retrieve, and delete data from the database tables according to your needs. In this article, we'll cover some of the most commonly used DML commands in SQL.

Syntax

INSERT Command Syntax

The syntax for the INSERT command is as follows:

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...);

UPDATE Command Syntax

The syntax for the UPDATE command is as follows:

UPDATE table_name
SET column1 = value1, column2 = value2,...
WHERE condition;

SELECT Command Syntax

The syntax for the SELECT command is as follows:

SELECT column1, column2, column3,...
FROM table_name
WHERE condition;

DELETE Command Syntax

The syntax for the DELETE command is as follows:

DELETE FROM table_name
WHERE condition;

Example

INSERT Command Example

INSERT INTO customers (name, email, phone)
VALUES ('John Doe', 'johndoe@example.com', '555-1234');

UPDATE Command Example

UPDATE customers
SET phone = '555-5678'
WHERE name = 'John Doe';

SELECT Command Example

SELECT name, email
FROM customers
WHERE phone = '555-5678';

DELETE Command Example

DELETE FROM customers
WHERE name = 'John Doe';

Output

The output of each DML command varies according to the command. It will either modify the data, retrieve the data, or delete the data from the database.

Explanation

INSERT Command Explanation

The INSERT command is used to add new data into the database. You must specify the name of the table and the values that you want to insert into the table.

UPDATE Command Explanation

The UPDATE command is used to modify existing data in the database. You must specify the name of the table, the name of the column, and the value that you want to change.

SELECT Command Explanation

The SELECT command is used to retrieve data from the database. You must specify the name of the table and the columns that you want to retrieve.

DELETE Command Explanation

The DELETE command is used to remove data from the database. You must specify the name of the table and the condition that indicates which rows are to be deleted.

Use

DML commands are used in various contexts. You can use them to maintain a database of customers, employees, orders, and other types of data. They are also useful in building web applications, mobile apps, and other types of software.

Important Points

• DML commands are used to manipulate data in database tables.
• INSERT command is used to add new data to the database.
• UPDATE command is used to modify existing data in the database.
• SELECT command is used to retrieve data from the database.
• DELETE command is used to remove data from the database.
• Each command requires a specific syntax and parameters to work correctly.

Summary

In this article, we covered some of the most commonly used DML commands in SQL. You learned how to use INSERT, UPDATE, SELECT, and DELETE commands to manipulate data in a database. You also learned about the syntax, example, output, explanation, use, important points, and summary of these commands. By applying this knowledge, you'll be able to work with databases and handle data with ease.