What is a UUID?

1. Definition

The UUID meaning is a universal unique identifier (universally unique Identifier), which is a software construction standard and is also used by the Open Software Foundation, OSF, to organize applications in a distributed computing environment ( Distributed Computing Environment, DCE) is part of the field.

2. function

The purpose of UID is to allow all elements in a distributed system to have unique identification information without the need to specify the information through the central control terminal. In this way, everyone can create a UUID that does not clash with others. In such a case, there is no need to consider the name duplication problem when the database is established. Currently the most widely used UUID is Microsoft's globally Unique Identifiers (GUIDs), while other important applications are the Linux ext2/ext3 file system, LUKS encryption partition, GNOME, KDE, Mac OS X, and so on.

3. Composition

A UUID is a number generated on a machine that guarantees that all machines in the same time and space are unique. Typically, the platform provides the generated APIs. Based on the standard calculations developed by the Open Software Foundation (OSF), the Ethernet card address, nanosecond time, chip ID code, and many possible digital UUID combinations are used: (1) The current date and time, the first part of the UUID is related to the time, and if you create a UUID, When a UUID is generated in a few seconds, the first part is different and the rest is the same. (2) clock sequence. (3) Globally unique IEEE machine identification number, if there is a network card, from the network card MAC address obtained, no network card is obtained in other ways. The only drawback to the UUID is that the resulting string will be longer. The most common use of UUID for this standard is the GUID of Microsoft (Globals Unique Identifiers). In ColdFusion, the UUID can be easily generated with the Createuuid () function in the form of: Xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx (8-4-4-16), where each x is 0-9 or a-f A hexadecimal number within the range. The standard UUID format is: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (8-4-4-4-12), which can be converted from cflib download CreateGUID () UDF. 4, the application of the benefits of using UUID in distributed software systems (such as: Dce/rpc, Com+,corba) can be reflected, it can ensure that each node generated by the identity will not be duplicated, and with the development of integrated technology such as Web services, the advantages of UUID will be more obvious. Depending on the specific mechanism used, the UUID must not only be guaranteed to be different from each other, or at least be very different from any other generic unique identifiers that were generated before the 3400 AD. The universal unique identifier can also be used to point to most possible objects. Microsoft and some other software companies tend to use a globally unique identifier (GUID), which is a type of generic unique identifier that can be used to point to building object module objects and other software components. The first universally unique identifier is a component of the Distributed computing Environment (DCE) that was created in the network computer system (NCS) and subsequently became the Open Software Foundation (OSF). Excerpt from Baidu

What is a UUID?