This documentation is valid for:

According to Wikipedia, a GUID or Globally Unique Identifier is a pseudo-random number employed in software applications. While each generated GUID is not guaranteed to be unique, the total number of unique keys is so large that the probability of the same number being generated twice is infinitesimally small.

The term GUID refers to Microsoft’s implementation of the Universally Unique Identifier (UUID) standard by Open Software Foundation (OSF). It is essentially a 16-byte number. It consists of 8 hexadecimal digits followed by a hyphen, then three groups of 4 hexadecimal digits each followed by a hyphen, then 12 hexadecimal digits. For example: {3F2504E0-4F89-11D3-9A0C-0305E82C3301}

The number of GUIDs theoretically possible is approximately 216 × 8 = 2128 = 25616 . This means that you would need to generate one trillion GUIDs every nanosecond for approximately 10 billion years to generate all the possible GUIDs.

As of GeneXus X Ev1, this type of data is supported natively.