As beginners in the field of web programming, a crucial concept that is learnt and implemented throughout one’s journey as a web programmer is the concept of CRUD Operations. CRUD Operations are basically operations that provide basic functionalities such as Create, Read, Update and Delete operations that must be performed by model or application. This CRUD operations paradigm is essential for constructing web applications because it provides a memorable framework for reminding developers of how to construct full, usable models. The CRUD acronym identifies all of the major functions that are inherent to relational databases and the applications used to manage them. Every operation in the CRUD acronym can be mapped to a standard Standard Query Language (SQL). 

 

There are four basic operations that are present in CRUD – 

 

  • CREATE –  The Create Operation allows users to create a new resource inside the application or record in the database.  In the SQL Relational Databases, the CREATE function is called INSERT. Thus, a new row is created and data is populated as per the attributes of the table.

 

  • READ – The Read Operation allows users to search and retrieve data and information from the database as per certain requirements and then read their values. Users may be able to find desired records using keywords, or by filtering the data based on customized criteria. In the SQL Relational Database, the READ function is called SELECT.  Thus, records are fetched from the table as per the criteria specified.

 

  • UPDATE – The Update Operation allows users to modify existing records that already exist in the application and the table. In order to fully change a record, users may have to modify information in multiple fields. For this operation, the UPDATE operation is utilized. In SQL, it corresponds to the UPDATE query.

 

  • DELETE – The Delete Operation allows users to delete resources within the application and from the database and table. The delete function allows users to remove records from a database that is no longer needed. This operation corresponds to the DELETE query in SQL that removes one or more records in the table. 

 

In a REST environment, CRUD corresponds to the HTTP methods POST, GET, PUT and DELETE methods, respectively. These are the fundamental elements of the persistent storage system. 

 

  •  CREATE – To create resources in a REST environment, we most commonly use the HTTP POST method. POST creates a new resource of the specified resource type. Upon successful creation, the server should return a header with a link to the newly-created resource, along with a HTTP response code of 201 (CREATED). Response: Status Code – 201 (CREATED). 

 

  • READ – To read resources in a REST environment, we use the GET method. Reading a resource should never change any information – it should only retrieve it. Even if you retrieve the same information 10 times, you should get the same response on the first call that you get on the last call. GET can be used to read an entire list of items. s, GET will return the HTML or JSON of the desired resource, along with a 200 (OK) response code. If there is an error, it most often will return a 404 (NOT FOUND) response code.

 

  • UPDATE – PUT is the HTTP method used for the CRUD operation, Update. This response includes a Status Code of 200 (OK) to signify that the operation was successful. Optionally, the response could use a Status Code of 204 (NO CONTENT) and not include a response body. This decision depends on the context.

 

  • DELETE – The CRUD operation Delete corresponds to the HTTP method DELETE. It is used to remove a resource from the system. Such a call, if successful, returns a response code of 204 (NO CONTENT), with no response body.  Response: Status Code – 204 (NO CONTENT). Calling DELETE on a resource that does not exist should not change the state of the system. The call should return a 404 response code (NOT FOUND) and do nothing. 

 

Thus, the CRUD paradigm are fundamental concepts of a usable storage model. They are crucial concepts necessary to construct such a system and implement it for different kinds of user functionalities. 

DISCLAIMER: The author is solely responsible for the views expressed in this article. The author carries the responsibility for citing and/or licensing of images utilized within the text.