A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Version 4 UUIDs are randomly generated and have 122 random bits, making collisions extremely unlikely.

How do I generate a UUID in PostgreSQL?

In PostgreSQL, you can use the uuid_generate_v4() function from the uuid-ossp extension. First enable the extension with 'CREATE EXTENSION IF NOT EXISTS "uuid-ossp";' then call SELECT uuid_generate_v4();

How to generate UUID in C#?

In C#, you can generate a UUID (called GUID in .NET) using Guid.NewGuid(). This creates a version 4 random UUID. Example: Guid myGuid = Guid.NewGuid(); string uuidString = myGuid.ToString();

What's the difference between UUID and GUID?

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same standard. GUID is Microsoft's implementation term for UUID. Both represent 128-bit unique identifiers following RFC 4122 specifications.

UUID Generator

Create version 4 random UUIDs instantly for your projects

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Understanding UUIDs

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Our generator creates version 4 UUIDs which are randomly generated, providing a practically unique identifier for your projects.

Common Uses for UUIDs

Database primary keys (PostgreSQL, MySQL, etc.)
Distributed systems identification
Session identifiers in web applications
Unique filenames for storage systems
Tracking unique events in analytics

UUID Format

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

Where each x is any hexadecimal digit (0-9, a-f) and y is one of 8, 9, a, or b.

Technical Details

Version 4 (random) UUIDs have 122 random bits
Collision probability is extremely low (1 in 2.71 quintillion)
Standardized in RFC 4122

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The Complete Guide to UUID Generators for Developers

In today's distributed computing environment, UUID generators have become essential tools for developers. Whether you're working with PostgreSQL's uuid_generate_v4, creating a unique ID in C#, or need a random UUID for your web application, understanding how to generate and use these identifiers is crucial.

What Makes UUIDs Special?

UUIDs (Universally Unique Identifiers) solve the problem of needing unique identifiers across distributed systems without centralized coordination. Unlike auto-incrementing IDs that require database coordination, UUIDs can be generated anywhere and still maintain uniqueness.

Popular UUID Generation Methods

PostgreSQL uuid_generate_v4(): The standard method for generating version 4 UUIDs in PostgreSQL databases
C# Guid.NewGuid(): Microsoft's implementation of UUID generation in .NET
AWS UUID generator: Various AWS Services like DynamoDB can generate unique identifiers
Bluetooth UUID generator: Specialized UUIDs used in BLE (Bluetooth Low Energy) devices

When to Use UUIDs

UUIDs are particularly useful in these scenarios:

Distributed Systems

When multiple systems need to generate IDs independently without coordination

Database Sharding

For horizontal partitioning where auto-increment IDs don't work across shards

Offline Capabilities

When clients need to generate IDs while offline before syncing with a server

Security

For unpredictable identifiers in security-sensitive applications

Performance Considerations

While UUIDs solve important problems, they come with tradeoffs:

Storage size: 128-bit UUIDs take more space than 32 or 64-bit integers
Indexing: Random UUIDs can cause index fragmentation in databases
Readability: UUIDs are harder for humans to read and remember than sequential IDs

External Resources

For more in-depth information about UUIDs and their implementations:

RFC 4122 Specification - The official UUID standard
PostgreSQL UUID Documentation
.NET Guid.NewGuid() Documentation
Wikipedia UUID Article
MySQL UUID Functions
UUID Tools - Additional UUID utilities
CockroachDB UUID Documentation
AWS DynamoDB UUID Best Practices
Bluetooth Assigned Numbers (UUIDs)