1. Introduction

Every kind of computing system work with data. Naturally, managing data is a crucial part of the operation lifecycle of such systems. Some data are transitory and, after being processed, can be discarded. Other data, however, are stored and kept available for future use.

For the second case, operators should be able to manage the stored data to keep the system functional and updated. We have particular data management operations according to the scope of computing systems. But, we have a small set of these operations commonly available for all kinds of computing systems. We call this set CRUD.

So, in this tutorial, we’ll learn what CRUD is and understand each one of its operations.

2. What Is CRUD?

CRUD refers to the four primary operations executed over data stored in a database: Create, Read, Update, and Delete.

The CRUD operations are the most basic data manipulation set. So, although we’re talking about CRUD in terms of data stored in a database (entries in a database), these operations are also observed in several stages of software development. 

For example, in an object-oriented programming project, programmers should design the classes and their methods to provide and allow the execution of CRUD operations.

In this way, let’s particularly understand each CRUD operation in the following subsections.

2.1. The C: Create

In short, the create operation means adding a new entry to a database. In other words, we can understand the create operation as adding new data to a database.

2.2. The R: Read

The read operation indicates recovering an entry stored in a database. So, after recovering the entry, the computing systems can use it to execute other operations (not necessarily CRUD-related) or exhibit its data to the system operator, for instance.

We should note that the entry to read must already be available in the database. Thus, any read operation relies on the previous execution of a create operation.

2.3. The U: Update

The update operation regards editing an entry in a database. It means modifying (fully or partially) the entry’s data.

So, as for the read operation, the entry to update must already exist in the database for accomplishing an update operation.

2.4. The D: Delete

The delete operation defines the remotion of an entry from a database. In such a way, after executing such an operation, a so-on existing entry is deleted and is no longer available in the database.

We can say that the successful execution of a delete operation relies on a previous successful execution of a create operation and immediately makes the read and update operations unavailable for the deleted entry.

3. The Data Lifecycle

The CRUD operations also depict the typical data lifecycle in a computing system. The computing system creates a piece of data once, reads and updates it one or more times as necessary, and finally, deletes the data when it is no longer required.

The following figure depicts the previously described CRUD-based data lifecycle:

CRUD lifecycle

It is relevant to note that what this data represents is not really important to the CRUD operations: we can work with any data category, from simple client registration forms to complex genome data, for example. So, the manner the systems execute CRUD operations can technically change, but the results are the same regardless of the data operated.

In this way, we can see CRUD operations as a broad and generic framework for data management in computing.

4. Conclusion

In this tutorial, we studied CRUD in the context of data storage. First, we explored the CRUD operations. Then, we briefly saw the CRUD-based data lifecycle.

We can conclude that CRUD represents crucial operations for data management. Due to that reason, most computing systems and programs implement it.

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