Ultimate CRUD vs REST Guide: Operations Simplified 101

REST and CRUD are two major concepts in the API industry. While REST is the most widely considered design style for Web APIs, CRUD helps in database applications. As organizations use REST API, they inherently rely on a RESTful Architecture. However, REST and CRUD operations resemble each other because REST is a superset of CRUD when performing HTTP methods. So why CRUD vs REST?

By design, CRUD is a cycle that can be transferred to REST. Permanence is a reasonable approach for applications to attenuate operational directives between clients and services, as stated in the context of CRUD. However, within its architectural principles, REST manages much more than permanence.

This article describes the operation of REST and CRUD. It briefs you with a basic understanding of CRUD vs REST along `with underlying principles. The article also discusses similarities and differences between REST and CRUD.

Table of Contents

• Prerequisites
• Introduction to REST 
• 5 Key Principles of REST
  • Statelessness
  • Layered System
  • Decoupled Service
  • Uniform Interface
  • Cache
• Key Operations in REST
• Introduction to CRUD
• 4 Key Principles of CRUD
• Operations in CRUD
• CRUD vs REST Similarities & Dissimilarities
• Parameters for Selecting between CRUD vs REST
• Conclusion

Prerequisites

• An idea of HTTP methods.

Introduction to REST

REST, an acronym for REpresentational State Transfer, is a popular Architectural Style used for developing an API. The foundation of REST was laid out in 2000 by computer scientist Dr. Roy Fielding in his doctoral thesis. He also mentioned that REST provides a relatively higher level of flexibility and freedom for developers.

As REST APIs provide a flexible, lightweight technique to integrate applications, it has emerged as the most widely used method for connecting components in microservices architectures.

5 Key Principles of REST

API enables an application or service to access resources within another application or service. This mechanism consists of two parts — the application or service accessing is called ‘client,’ and the application or service containing resources is called ‘server.’

Based on the application, APIs are defined by different protocols like — SOAP, XML-RPC, or JSON-RPC that impose a strict framework on developers. However, REST APIs can be developed using any programming language, and it supports a variety of data formats. Following are the requirement that satisfies REST Design Principles:

1) Statelessness

Statelessness is the guiding principle of REST Architecture that mandates commands offered between client and server. ‘Stateless requests’ initiate communication between client and server, where each request needs to include all necessary information to process it.

2) Layered System

A layered system makes REST Architecture scalable. As none of the layers can see into others, the calls and responses go through different layers. This principle allows new commands to be added without impacting previous commands and their functionality.

3) Decoupled Service

Client-Server Decoupling shows the nature of the separation between client and server. While a service listens to requests and has multiple capabilities, any request made by consumers is either accepted or rejected by the server.

4) Uniform Interface

REST architecture defines a uniform contract, prohibiting the use of multiple or self-contained interfaces within an API. No matter where the request initiates, all APIs requesting the same resource should look alike (Idempotent).

5) Cache

Resources should be cacheable on the client or server side because it helps to mitigate constraints of statelessness. Caching improves not only performance on the client-side but also grows scalability on the server-side.

Key Operations in REST

REST guidelines suggest using the HTTP method. Below are five commands to perform necessary actions:

1) HTTP GET: It is used to retrieve resource representation/information with no modifications. As ‘GET’ requests do not change the resource’s state, it is considered a safe method. Additionally, GET APIs are idempotent because they produce the same result, even when multiple identical requests occur. Below are a few cases while using an HTTP GET API:

• If the resource is found on the server, it must return HTTP response code 200 (OK) – along with the response body. Below is an example of an HTTP GET request:

Request:

Response:

• If a resource is not found on the server, it should return HTTP response code 404 (NOT FOUND).
• Similarly, if it is discovered that a GET request itself is not correctly formed, then the server will return the response code 400 (BAD REQUEST).

2) HTTP POST: It is used to create new subresources in an existing directory. Below are the conditions that exist in HTTP POST API:

• If a new resource is created in the collection of resources, then the response should be HTTP response code 201.
• If the action performed by the POST method does not result in the creation of a new resource, either HTTP response code 200 (OK) or 204 (No Content) is the response status.

Suppose, the task is to add a new customer to existing customer data, use the below POST command:

3) HTTP PUT: It is primarily used to update existing resources. Following are the cases that exist in HTTP PUT API:

• If a new resource has been created, the origin server must inform the user with HTTP response code 201 (Created).
• However, if an existing resource undergoes modification, either the 200 (OK) or 204 (No Content) response codes are sent to indicate successful completion of the request.
• In addition, responses to the PUT method are not cacheable. If the request passes through a cache and the request-URI identifies one or more recently cached entities, such entries can be treated as stale. 

If the task was to update customer name, use the below command:

4) HTTP DELETE: These functions help mainly delete resources identified by URI. This operation is idempotent. Following are events that may occur:

• A successive delete response should return HTTP response code 200 (OK).
• If the action is queued, the response code would be 202 (Accepted).
• If the action is performed, but the response does not include an entity, the response code is 204 (No Content).

For instance, your task is to delete an existing record, use the below command:

5) HTTP PATCH: These equests are used to make partial updates on resources. Although PUT requests modify a resource identity, the PATCH method is still the correct choice for partially updating an existing resource. The PATCH method is not universal and may not support all browsers, servers, and web applications. Below is the command to use the PATCH method:

Syntax:

Output:

REST also includes many other HTTP methods like — TRACE, CONNECT, and OPTIONS.

Introduction to CRUD

CRUD is an acronym for Create, Read, Update, and Delete commands. These four major functions are primitive guidance for software developers that interact with databases.

CRUD operations are cyclic in nature rather than being an architectural system. For any given dynamic website, there are multiple CRUD Cycles that exist. Despite its origin from databases, it now maps the design principle of dynamic applications like HTTP, SQL, and DDS.`

4 Key Principles of CRUD

Here are the simple principles of CRUD:

• Create: A procedure that generates new records through an ‘INSERT’ statement.
• Read: A procedure used to read/retrieve data based on desired input parameters.
• Update: This is a procedure used to modify records without overwriting them.
• Delete: A procedure used to remove one or more entries entirely.

Operations in CRUD

Any organization that tracks data requires a system that provides organized storage in a database. A Relational Database consists of data systematically arranged in rows and columns. CRUD refers to four functions implemented on a database that acronyms create, read, update, and delete.

As Relational Databases are a persistent layer in software applications, CRUD functionalities are performed in SQL, and the below table summarizes operations:

Similarly, HTTP methods also have CRUD Mnemonic for storage semantics. As CRUD represents fundamental operations, it is the bare minimum requirement of software for end-users. REST is the “Superset” of CRUD used for HTTP resources.

CRUD vs REST Similarities & Dissimilarities

In CRUD vs REST, REST has a robust architecture centred around resources and hypermedia by HTTP protocols. CRUD is a cycle meant to maintain permanent records in Database Management Systems.

REST has the foundation of RESTful architecture that supports HTTP for the web interface, whereas CRUD can be mapped to DDS, SQL, or HTTP methods. While CRUD principles have striking similarities in REST, one must note that REST is not limited to CRUD operations so we can have a better understanding of CRUD vs REST.

Although CRUD can be mapped to REST from a design perspective, REST governs more permanence than CRUD to mitigate operation commands between clients and services from CRUD vs REST. CRUD is an action performed to write data into a database, whereas REST is compatible with any object or resource, from a media file, website to document, and other services.

Parameters for Selecting between CRUD vs REST

There are many features that aviate CRUD vs REST operation in organizations. When given a choice to pick from CRUD vs REST, Developers choose CRUD to implement the necessary functions of persistent storage. However, below are a few parameters that make REST reliable:

• Scalability: In CRUD vs REST, the REST architecture adheres to the uniform interface, prohibiting the use of multiple interfaces within an API. This mechanism makes REST scalable.
• Simplicity: In CRUD vs REST, REST is stateless and decouples client and server, a request contains all necessary information.
• Systematized: In CRUD vs REST, REST makes efficient use of the cache mechanism by determining the responses sent by the server.

Conclusion

Every developer, when asked CRUD vs REST, prefers CRUD for performing database-related operations on websites or applications. However, due to the limited scope of robust development, organizations rely on RESTful Architecture. Not only REST provides various exclusive features that scale web services, but with its simplicity and high performance, REST Architecture is massively accepted to build API.

This article has described the operation of REST and CRUD. It briefed you with an understanding of CRUD vs REST along with underlying principles.

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