You can get the GUID back by using OUTPUT. This works when you’re inserting multiple records also. CREATE TABLE dbo.GuidPk ( ColGuid uniqueidentifier NOT NULL DEFAULT NewSequentialID(), Col2 int NOT NULL ) GO DECLARE @op TABLE ( ColGuid uniqueidentifier ) INSERT INTO dbo.GuidPk ( Col2 ) OUTPUT inserted.ColGuid INTO @op VALUES (1) SELECT * FROM … Read more
Here’s an excellent breakdown by Raymond Chen
Performance Benchmarks Catch exception: 10,000 good: 63,668 ticks 10,000 bad: 6,435,609 ticks Regex Pre-Screen: 10,000 good: 637,633 ticks 10,000 bad: 717,894 ticks COM Interop CLSIDFromString 10,000 good: 126,120 ticks 10,000 bad: 23,134 ticks COM Intertop (Fastest) Answer: /// <summary> /// Attempts to convert a string to a guid. /// </summary> /// <param name=”s”>The string to … Read more
— Update — As of January 9th, 2015. the solution is now implemented in Rails 5 ActiveRecord’s secure token implementation. — Rails 4 & 3 — Just for future reference, creating safe random token and ensuring it’s uniqueness for the model (when using Ruby 1.9 and ActiveRecord): class ModelName < ActiveRecord::Base before_create :generate_token protected def … Read more
[Edited 2021-10-16 to reflect latest best-practices for producing RFC4122-compliant UUIDs] Most readers here will want to use the uuid module. It is well-tested and supported. The crypto.randomUUID() function is an emerging standard that is supported in Node.js and an increasing number of browsers. If neither of those work for you, there is this method (based … Read more
Yes, you can. Since GUIDs are 128 bits long, there is admittedly a minute possibility of a clash—but the word “minute” is nowhere near strong enough. There are so many GUIDs that if you generate several trillion of them randomly, you’re still more likely to get hit by a meteorite than to have even one … Read more
As mentioned by @bacar, RFC 4122 §4.3 defines a way to create a name-based UUID. The advantage of doing this (over just using a MD5 hash) is that these are guaranteed not to collide with non-named-based UUIDs, and have a very (very) small possibility of collision with other name-based UUIDs. There’s no native support in … Read more
Currently, UUID’s are as specified in RFC4122. An often neglected edge case is the NIL UUID, noted here. The following regex takes this into account and will return a match for a NIL UUID. See below for a UUID which only accepts non-NIL UUIDs. Both of these solutions are for versions 1 to 5 (see … Read more
My DBA asked me when I asked about the best way to store GUIDs for my objects why I needed to store 16 bytes when I could do the same thing in 4 bytes with an Integer. Since he put that challenge out there to me I thought now was a good time to mention … Read more
[[UIDevice currentDevice] uniqueIdentifier] Returns the Unique ID of your iPhone. EDIT: -[UIDevice uniqueIdentifier] is now deprecated and apps are being rejected from the App Store for using it. The method below is now the preferred approach. If you need to create several UUID, just use this method (with ARC): + (NSString *)GetUUID { CFUUIDRef theUUID … Read more