Full detailed explanation of DataTypes.UUIDV4 on Sequelize

 

Here's the explanation of DataTypes.UUIDV4 in Sequelize in English:

1. What is UUID?

UUID (Universally Unique Identifier) is an identifier used to uniquely identify information without relying on a central authority or manager. A UUID consists of 32 hexadecimal characters, separated by hyphens, in the following format:

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

• x is a hexadecimal digit (0-9, a-f).
• 4 indicates that this is a UUID version 4.
• y is a hexadecimal digit that can be 8, 9, a, or b, indicating the UUID version.

2. UUID Version 4 (UUIDV4)

UUID version 4 (UUIDV4) is the most commonly used version of UUID because it is random. Unlike UUID version 1, which relies on timestamps and network information, UUID version 4 generates a unique identifier based on random numbers.

UUIDV4 is created by generating random numbers while conforming to the UUID format. There are many algorithms or libraries to generate UUIDV4, one of which is the uuid library commonly used in projects.

Example of a UUID version 4:

a3c3e9b4-45f2-4d0a-a4c1-4f72b39c8d8b

3. Using DataTypes.UUIDV4 in Sequelize

Sequelize provides DataTypes.UUIDV4 to help generate and store UUID version 4 automatically in your database column.

Here’s an example of using it in a Sequelize model:

import { Sequelize } from "sequelize";
import db from "../config/Database.js";

const { DataTypes } = Sequelize;

const Users = db.define('users', {
    uuid: {
        type: DataTypes.UUIDV4,
        defaultValue: DataTypes.UUIDV4, // Set default to UUIDV4
        allowNull: false,
        primaryKey: true
    },
    name: {
        type: DataTypes.STRING,
        allowNull: false
    }
}, {
    freezeTableName: true
});

export default Users;

• type: DataTypes.UUIDV4: Specifies that the uuid column will use UUID version 4 as the data type.
• defaultValue: DataTypes.UUIDV4: Sets the default value for the uuid column to be a newly generated UUID version 4 if no value is provided.
• allowNull: false: Ensures that the uuid column cannot be null, meaning every User entity must have a valid UUID.

4. Advantages of Using UUIDV4

• Uniqueness: UUIDs are globally unique, and the chances of duplication are extremely low, even with large-scale use.
• Security: UUIDs are safer to use as identifiers because they are random and do not expose sensitive information (like timestamps or IP addresses).
• Distributed Systems: UUIDs enable creating entities in distributed systems without requiring coordination from a central server since each UUID is guaranteed to be unique.
• Portability: UUIDs are not tied to specific systems or devices, so they can be used across various platforms and applications.

5. Disadvantages of UUIDV4

• String Length: UUIDV4 is longer (32 characters) compared to a regular integer, which could potentially impact database performance when used extensively.
• No Time Order: UUID version 4 is generated randomly, so there is no inherent time order in the UUID itself. If you need time-based ordering, UUID version 1 might be a better choice.

6. When to Use UUIDV4?

UUIDV4 is suitable when:

• You need a globally unique identifier.
• You are working with distributed systems that do not want to depend on sequential IDs generated by a single server.
• You want to avoid exposing information about objects that could be hidden behind a more predictable ID (like numerical IDs).

However, if performance is a concern and numerical IDs are more efficient, UUIDV4 might not be the best choice.

Conclusion

DataTypes.UUIDV4 in Sequelize allows you to generate and store UUID version 4, a randomly generated unique identifier. UUID version 4 is commonly used because of its high uniqueness, making it ideal for distributed applications or systems that need globally unique identifiers that are difficult to guess.