CRUD Operations: A Simple Guide For 2021 In 5 Easy Points


Working with a database means one has to manipulate the data that is raw to a meaningful form before one can gain insights into it. This means one has to perform several operations like read, create, update or delete data pieces. And those operations are precisely what are called the CRUD operations. Since most databases use SQL, it is important to understand the working of these CRUD operations in SQL. 

  1. Definition
  2. Explaining CRUD operations
  3. CRUD components
  4. Applications of CRUD
  5. What is CRUD testing?

1) Definition

What is CRUD? CRUD stands for the four functions most important in CRUD operations and is an acronym for CRUD- Create, Read, Update and Delete, which is essential to running any storage application and database operations. A persistent device in the storage means the device even powered off continues to retain power like a solid-state drive or hard disk. In stark contrast, the RAM (random access memory) and cache are great examples of memory that is volatile, meaning they store data that doesn’t get erased even when powered off. 

2) Explaining CRUD operations

Organizations keep track of relevant data for their operations related to accounts, customer data, health data, payment information, etc. which require the records to be stored and managed in a data storage hardware device that can be easily manipulated using software applications and can provide persistent storage and access in the electronic form.

Though the forms of databases like graph databases, hierarchical databases, object-oriented databases etc., may be different, they are all relational database management systems, aka RDBMS. Such databases like the Microsoft SQL Server, MySQL or Oracle Database popularly use table form to maintain the data in rows and columns and interconnected to the table network through keywords and complementary information known as foreign and primary keys.

What is CRUD operations in the computer programming language? CRUD operations refer to the four basic functions of all persistent storage devices which are used in relational database applications and executed by mapping to a SQL statement, DDS operation or by a standard HTTP method including user-interface conventions that helps in searching, viewing, modifying information etc. using the computer-based reports and forms. CRUD is thus data-oriented and uses standardized HTTP action verbs.

3) CRUD components

In 1990 Haim Kilov was responsible for the article, “From semantic to object-oriented data modelling”, mentioning CRUD operations. It was James Martin in his book of 1983, Managing the Data-base Environment, who made the term popular.

In it, CRUD meaning CREATE procedures were mentioned as performing the INSERT statement when creating a record, READ procedures as Reading table records based on the primary keyed input parameter, UPDATE procedures as Executing UPDATE statement on the table or record using the specified primary key and DELETE procedures as Deleting the specified row in the WHERE clause. Note that all these operations on a record are within the WHERE clause of the statement and that in a relational database, the rows of the table are tuples or records and columns the specific attribute or field. 

The four CRUD operations can perform using a graphical user interface or code.


This CRUD applications function permits creating a new database record. When using the SQL relational application, it is called INSERT though the Oracle HCM Cloud uses to create. Note that rows can be added and columns filled with the attributes using this operation. A system administrator may also be able to add new columns or attributes to the table.


Similar to the search function, and the read function permits users to retrieve, read values of and search for specific records in the table using keywords or filtering data using a customized criterion. For Ex: Searching a car database with the keyword “1996 Toyota Corolla”.


This function permits the modification of the existing database record and may involve modifying multiple fields of information. For Ex: Adding a new entry to personal information may involve adding in name, date of birth, address and more before updating the table information.


This function permits users to remove/delete database records no longer needed. Both Oracle HCM Cloud and SQL have the delete function. Some RDBMS-(Relational Database Management System) applications may allow a hard/soft delete where the hard delete is permanent in nature, and soft delete just updates the row status indicating that it has been deleted while preserving the data present intact.

4) Applications of CRUD

CRUD operations are popular in most RDBMS applications and are versatile functions used in a variety of database, different industry verticals and business models. Let’s take the example of how CRUD is implemented in the human resource application.

CRUD in HR-Human Resources operations:

The HR department normally maintains database records of existing employees to manage staff records and well-being. Such records have

  • An Employees Table with attributes like employee identification number, first and last name, home address, contact number, work location, and such details.
  • The HR Data Table has attributes like employee ID, employee’s payroll information, social security number, salary etc.
  • The Locations Table contains attributes like building ID, company’s physical locations, zip code, address, name of the manager, etc., for each physical location etc.

Whenever a new hire takes place, data is added to relevant records on the relevant tables like payroll, employees table etc. The HR department creates a new record and updates it to reflect the changes. When the enterprise needs to send a letter, it simply reads the employees table to select the relevant personal details, or when the employee leaves their service, they simply need to do a soft delete to reflect the change using CRUD operations.

5) What is CRUD testing?

CRUD testing is the name of a black-box testing technique to test CRUD definition, the functionality and validation of the software product. It is used in SQL database testing and a variety of databases to ensure data integrity, proper data mapping, business rules accuracy and maintaining of ACID properties.


Here we have studied the 4 important functions of CRUD operations in database management with an example of how it comes of use in the CRUD example of the HR department. CRUD stands for creating, read, update, delete operations, which are very helpful across databases, business applications and in managing eCommerce stores, forums, social media websites etc., supported by an RDBMS database by enabling better management of data to achieve business objectives.

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