What is CRUD?

CRUD stands for Create, Read, Update and Delete. Web apps are created to do these four operations. Using Twitter, I will explain how these operations work.

Prerequisites

• Understanding how the Internet works

• Requests and responses

Create

Create is the operation used to refer to POST requests. A POST request is used to send data to the server. According to the MDN,

The POST method submits an entity to the specified resource, often causing a change in state or side effects on the server.

For example,

When you create a new tweet, a POST request is sent to the server. The tweet is saved in the database and added to the timeline.

A POST request can also be initiated when a new Twitter account is created.

Read

Read is the operation used to refer to GET requests. A GET request is used to retrieve data from the server. According to the MDN,

The GET method requests a representation of the specified resource. Requests using GET should only retrieve data.

For example,

When you view a tweet, a GET request is sent to the server and the tweet is sent as a response.

Update

Update is the operation used to refer to PUT requests. A PUT request is used to add data that is tied to an existing resource in the database. According to the MDN,

The HTTP PUT request method creates a new resource or replaces a representation of the target resource with the request payload.

For example,

When you like or retweet a tweet, a PUT request is sent. The server adds the number of likes or retweets in the server and sends back a response

Delete

Delete is the operation used to refer to DELETE requests. A DELETE request is used to delete data from the server. According to the MDN,

The HTTP DELETE request method deletes the specified resource.

For example,

When you delete a tweet, a DELETE request is sent to the server. The tweet is deleted and the response is sent back. Then, the tweet is removed from your profile.

In the video above, the retweet is undone by sending a DELETE request. The number of retweets is reduced and updated as a response to the request.

Summary

• CRUD stands for Create, Read, Update and Delete.

• Create is the operation used to refer to POST requests.

• A POST request is used to send data to the server.

• Read is the operation used to refer to GET requests.

• A GET request is used to retrieve data from the server.

• Update is the operation used to refer to PUT requests.

• A PUT request is used to add data that is tied to an existing resource in the database.

• Delete is the operation used to refer to DELETE requests.

• A DELETE request is used to delete data from the server.