Understanding what CRUD is in 1 minute

In programming, CRUD is an acronym that represents the four basic operations that can be performed on data:

• Create
• Read
• Update
• Delete

This term is often used in databases, but also in web/mobile/software development for the operations available in an API.

In the rest of this article, we will use SQL query examples to illustrate the different operations

Create

The Create operation allows adding new data.

For example, creating a new user in the database with INSERT:

INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');

Read

The Read operation allows retrieving data.

For example, reading and filtering all users living in Paris, with SELECT...WHERE:

SELECT * FROM users WHERE city = 'Paris';

Update

The Update operation allows modifying existing data.

For example, if a user updates their email address, this action corresponds to an UPDATE query in SQL:

UPDATE users SET email = 'alice.new@example.com' WHERE id = 1;

Delete

The Delete operation simply allows deleting data.

This is what happens when a user is deleted with a DELETE query:

DELETE FROM users WHERE id = 1;

CRUD in REST APIs

We also talk about CRUD in REST APIs, because each operation corresponds to an HTTP method:

• Create → POST
• Read → GET
• Update → PUT or PATCH
• Delete → DELETE

If you're not familiar with this, you can read our dedicated article on REST APIs to better understand!