uuid

This question already has an answer here: iPhone/iPad unique identifier BESIDES UUID/UDID? 6 answers Some people say UDID (Unique Device IDentifier) and some say UUID (Universally Unique IDentifier) . Are they are the same or not? What are the differences between them? UUID (Universally Unique IDentifier) Is on a per-app basis. identifies an app on a device. As long as the user doesn’t completely delete the app, then this identifier will persist between app launches, and at least let you identify the same user using a particular app on a device. Unfortunately, if the user completely deletes

Summary: I'm developing a persistent Java web application, and I need to make sure that all resources I persist have globally unique identifiers to prevent duplicates. The Fine Print: I'm not using an RDBMS, so I don't have any fancy sequence generators (such as the one provided by Oracle) I'd like it to be fast, preferably all in memory - I'd rather not have to open up a file and increment some value It needs to be thread safe (I'm anticipating that only one JVM at a time will need to generate IDs) There needs to be consistency across instantiations of the JVM. If the server shuts down and

I've read the man page, but I do not undestand what name and namespace are for. For version 3 and version 5 UUIDs the additional command line arguments namespace and name have to be given. The namespace is either a UUID in string representation or an identifier for internally pre-defined namespace UUIDs (currently known are "ns:DNS", "ns:URL", "ns:OID", and "ns:X500"). The name is a string of arbitrary length. The namespace: The namespace is either a UUID in string representation or an Does it mean that I need to store it (UUID v4) somewhere in relation with the generated UUID v5? In either

We're considering using UUID values as primary keys for our MySQL database. The data being inserted is generated from dozens, hundreds, or even thousands of remote computers and being inserted at a rate of 100-40,000 inserts per second, and we'll never do any updates. The database itself will typically get to around 50M records before we start to cull data, so not a massive database, but not tiny either. We're also planing to run on InnoDB, though we are open to changing that if there is a better engine for what we're doing. We were ready to go with Java's Type 4 UUID, but in testing have been

select case a when 0 then 1 else ( select max (uuid) from t_user) + 1 end as b from ( select count (uuid) as a from t_user) 转载于:https://www.cnblogs.com/BrightMoon/p/3581010.html 来源： https://blog.csdn.net/weixin_30546189/article/details/99149358