Judgement of codes in database

GUID (Global Uniform Identifier) refers to a number generated on a machine, which is guaranteed to be unique to all machines at the same time and space. Usually the platform provides an API to generate GUID. The generation algorithm is very interesting, using Ethernet card address, nanosecond time, chip ID code, and many possible numbers. The only drawback of GUID is that the generated result string will be very large. "

1.GUID is an integer of 128 bits (16 bytes), which can be used between all computers and networks with a unique identifier.

2. globally unique identifier

The format of is "xxxxxxxx-xxxx-xxxx-xxxx-", where each

x

be

0-9

or

a-f

Hexadecimal number in the range. For example: 337F2b-7A34-4F50-9141-bab9e64788.

Is effective.

guid,globally unique identifier

Value.

No two computers in the world will produce duplicates.

guid,globally unique identifier

Value. guid,globally unique identifier

It is mainly used to assign a unique identifier in a network or system with multiple nodes and computers.

4. at

Windows operating system

On the platform, GUID

Widely used: registry, class and interface identification, database, and even automatically generated machine names and directory names.

Programming tools usually have methods to generate these GUID:

Using cltrG to generate in delphi

You can also use the () function.