uuid

What's your opinion on using UUIDs as database row identifiers, particularly in web apps?

I've always preferred to use long integers as primary keys in databases, for simplicity and (assumed) speed. But when using a REST or Rails-like URL scheme for object instances, I'd then end up with URLs like this: http://example.com/user/783 And then the assumption is that there are also users with IDs of 782, 781, ..., 2, and 1. Assu...

Advantages and disadvantages of GUID / UUID database keys

I've worked on a number of database systems in the past where moving entries between databases would have been made a lot easier if all the database keys had been GUID / UUID values. I've considered going down this path a few times, but there's always a bit of uncertainty, especially around performance and un-read-out-over-the-phone-able...

How to create a GUID / UUID in Javascript?

I'm trying to create globally-unique identifiers in Javascript. I'm not sure what routines are available on all browsers, how "random" and seeded the built-in random number generator is, etc.. The GUID / UUID should be at least 32 characters and should stay in the ASCII range to avoid trouble when passing them around. ...

Generating a unique ID in PHP

I'm trying to generate a unique ID in php in order to store user-uploaded content on a FS without conflicts. I'm using php, and at the moment this little snippet is responsible for generating the UID: $id = tempnam (".", ""); unlink($id); $id = substr($id, 2); This code is hideous: it creates a temporary file on the FS and deletes it...

Most efficient data type for UUID in database besides a native UUID.

What would be the most efficient data type to store a UUID/GUID in databases that do not have a native UUID/GUID data type? 2 BIGINTs? And what would be the most efficient code (C# preferred) to convert to and from a GUID to that type? Thanks. ...

Is there any difference between a GUID and a UUID?

I see these 2 acronyms thrown around, and I was wondering if there are any differences between a GUID and a UUID? ...

Is there a method to generate a standard 128bit GUID (UUID) on the Mac?

Is there a built in function equivalent to .NET's Guid.NewGuid(); in Cocoa? My desire is to produce a string along the lines of 550e8400-e29b-41d4-a716-446655440000 which represents a unique identifier. ...

What is a UUID?

Well, what is one? ...

Do I need a UUID to program for the iPhone?

Do I need a UUID to program for the iPhone? I was told I need this, how can I get a UUID ...

How can I assemble bits into a long to create a unique ID?

I would like to write a utility that will provide me with a relatively unique ID in Java. Something pretty simple, like x bits from timestamp + y bits from random number. So, how would I implement the following method: long getUniqueID() { long timestamp = System.currentTimeMillis(); long random = some random long ... ...

Generate UUID in Java

If I'm using Long uuid = UUID.randomUUID().getMostSignificantBits() how likely is it to get a collision. It cuts of the least significant bits, so there is a possibility that you run into a collision, right? ...

Extracting MAC addresses from UUIDs

A program that I work on assumes that the UUID generated by the Windows RPC API call UuidCreateSequential() contains the MAC address of the primary ethernet adapter. Is this assumption correct or should I use a different method to get the MAC address? ...

what is the algorithm used to generate those little gravatar identicon images?

Naturally, one would suspect that the algorithm creates images that are: highly unlikely to produce the same identicon twice; and capable of ensuring that each identicon is sufficiently distinctive as to not appear too similar to any other identicon ...

How to create a GUID/UUID using the iPhone SDK

I want to be able to create a GUID/UUID on the iPhone but I can't see any way to do it. The intention is to be able to create keys for distributed data, that are all unique. Do I need some third-party code or is there a built in way to do this in the SDK? I have tried Googling it, but I could find anything. ...

How to create a GUID in Python

How do I create a GUID in Python that is platform independent? I hear there is a method using ActivePython on Windows but it's Windows only because it uses COM. Is there a method using plain Python? ...

Platform-independent GUID generation in C++?

What is the best way to programmatically generate a GUID or UUID in C++ without relying on a platform-specific tool? I am trying to make unique identifiers for objects in a simulation, but can't rely on Microsoft's implementation as the project is cross-platform. Notes: Since this is for a simulator, I don't really need cryptographic...

Storing MySQL GUID/UUIDs

This is the best way I could come up with to convert a MySQL GUID/UUID generated by UUID() to a binary(16): UNHEX(REPLACE(UUID(),'-','')) And then storing it in a BINARY(16) Are there any implications of doing it this way that I should know of? ...

Select a UUID

We need to generate UUIDs for every single entry we store in the backend. As I read in Wikipedia: Uuid Java implementation, there are 3 available UUID generators: - Standard Java UUID generator(which only support version 3 and 4) - JUG which support all the version but 2 - UUID which only support version 1 (MAC address based) Please...

Is it safe to use Python UUID module generated values in URL's of a webpage?

Is it safe to use Python UUID module generated values in URL's of a webpage? Wnat to use those ID's as part of URL's. Are there any non-safe characters ever generated by Python UUID that shouldn't be in URL's? ...

When are you truly forced to use UUID as part of the design?

I don't really see the point of UUID. I know the probability of a collision is effectively nil, but effectively nil is not even close to impossible. Can somebody give an example where you have no choice but to use UUID? From all the uses I've seen, I can see an alternative design without UUID. Sure the design might be slightly more c...