In the world of computer programming and software development, CRUD is a very important term. Without CRUD operations, it’s difficult for software developers to get things done in database applications. But what is CRUD? The acronym CRUD stands for Create, Read, Update and Delete. These operations are necessary to interact with database applications. In addition, CRUD operations are also an essential part of API development (REST APIs.)
In this article, we’ll discuss what is CRUD and what CRU operations are in a database. We’ll also discuss how CRUD operations relate to REST APIs.
Table of Contents
What Is CRUD?
The acronym CRUD consists of four basic operations – C: Create, R: Read, U: Update, D: Delete. These are essentially the fundamental operations for implementing persistent storage applications. Persistent storage is any storage device that retains data even after the device is switched/powered off.
CRUD operations are inherent to database applications, especially relational databases like MySQL. Using these functions, developers can perform different operations on the data within a database. However, we can also implement these functions on object databases, XML databases, document databases, binary files, and text files. For instance, we can create an MS Word file, read it, update it, and delete it if we want.
Different protocols like HTML and programming languages have their own version of CRUD. For instance, in SQL (Structured Query Language), these operations are called Insert, Select, Update, and Delete.
Similarly, HTTP has its equivalent of CRUD operations called POST, GET, PUT, and DELETE. Hence, CRUD operations are an essential part of API and website development as these two involve HTTP protocol.
How Do CRUD Operations Work?
In this section, we’ll discuss how CRUD operations work in relational database applications, as it’s one of the most used databases.
A relational database consists of tables with several rows and columns. Within a relational database, a row is referred to as a record, whereas the table’s columns are known as attributes. We can use the CRUD functions to perform different operations on the data saved in the database. We can use code or a GUI (Graphical User Interface) to perform CRUD operations.
Here is how CRUD works in a relational database:
The Create operation allows us to create a new record in a database. In other words, we can use the Create function to add a new record to a relational database. The Create function is called Insert in a SQL relational database.
The CRUD operation Read is somewhat like a search function. We can use it to search, retrieve and read records in the database. Some relational databases enable users to use specific keywords or filters to find their desired records in the table. For example, if we have a database of movies, we can use the keywords “Inception 2010” or use filters such as genre or release year.
We use the Update function when we want to change/modify existing records or information saved in the CRUD database. However, if you want to change the record completely, you may have to change the information in multiple fields. For instance, say we have a database of a bakery consisting of all the food items with attributes like name, price, ingredients, etc. Now, if we want to add a new ingredient to the dish and change its price, we have to modify the ‘price’ and ‘ingredients’ attributes.
The Delete function, as the name suggests, enables users to remove a record or records from the database. You can use this function when you no longer need a record.
How Does CRUD Relate to REST APIs?
Now that we know what is CRUD in a database, let’s discuss what is CRUD in APIs.
Developers usually use SOAP (a protocol) or REST (an architectural style) to build APIs. While both these approaches have their own benefits, many developers prefer REST because of its simplicity, ease of use, and CRUD-oriented services. REST APIs support four different HTTP methods for data manipulation, and each operation in the CRUD acronym can be mapped to an HTTP method as follows:
Create – POST
In a REST environment, we use POST to create new resources. For instance, let’s say we have a REST-based system for a home decor shop that keeps track of different products and their prices. Now, if we want to add a new item to the stored list of products and the product objects are stored in a products resource, we would use a POST request.
Read – GET
If we want to read resources, the GET HTTP method is used. For instance, in the above example of the REST-based system for a home decor shop, we could use GET to retrieve the entire list of home decor products.
The purpose of Read is to retrieve information, so it shouldn’t change any information. Every time you call GET, it should return the same information.
Update – PUT
We use the PUT HTTP method to update a resource in a REST environment. For instance, if we want to update the price of a product in the above example, we would use PUT. PUT essentially lets you update the information in the database.
Delete – DELETE
The DELETE HTTP method allows us to remove a resource from the system. For example, let’s say the home decor shop isn’t selling a specific product anymore. If we want to remove that from the database, we will use DELETE.
Frequently Asked Questions (FAQs)
What does CRUD stand for?
The acronym CRUD stands for Create, Read, Update and Delete. However, different protocols and programming languages have their versions of CRUD. For example, CRUD operations are called Insert, Select, Update, and Delete in SQL. In HTTP, CRUD operations correspond to the HTTP methods POST, GET, PUT and DELETE.
What is meant by CRUD?
The CRUD acronym consists of four functions that are inherent to database applications, such as relational databases like MySQL. The CRUD functionality allows users to perform different operations on the data within a database.
What is CRUD in API?
REST APIs support four HTTP methods for data manipulation: POST, GET, PUT and DELETE. Each operation in the CRUD acronym can be mapped to one of these HTTP methods – Create = POST, Read = GET, Update = PUT, Delete = DELETE.
What is SQL CRUD?
In SQL, CRUD operations are called Insert, Select, Update, and Delete.