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The Internet Engineering Task Force (IETF) is the premier standards development organisation for the Internet. One of the ways that their work finds its way to the public in general and to engineers and techninians in particular is via documents, specifically RFCs (RFC stood originally for Requests For Comments). Each one is numbered and they describe fundamentals of the Internet, with RFCs ranging from core building blocks such as TCP/IP:

  • RFC 793 Transmission Control Protocol (TCP)
  • RFC 791 Internet Protocol (IP)

protocols that you and I deal with more closely and regularly, such as:

as well as somewhat more "unusual" protocols, such as RFC1149, and even non-protocol defining RFCs such as:

  • RFC2119 Key words for use in RFCs to Indicate Requirement Levels

which is as wonderful as it is useful and meta.

RFCs remain essential to how and why things work.

In CDS modelling there are many built-in types, such as Boolean, Integer, DateTime and more. One of these built-in types is UUID, the type behind the common aspect cuid, which is defined thus:

aspect cuid {
  key ID : UUID;
}

This built-in type UUID is compliant with a specific standard described in an RFC document. What is that RFC document's number?

This is a question from the June Developer Challenge on CAP Knowledge. And don't forget: always submit your answer as a hash, on its own - read the Taking part section of the intro post for more info. At the end of today, this question will be updated with links to further reading on this topic.

Further info:

  • The Core / Built-in Types topic in Capire has the list of types and links to reuse types and aspects (which includes cuid) as well as how the types relate to e.g. OData and HANA types.
34 Comments
furkan5
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SachinArtani
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FlorianP1
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Swathi_SAP_Philomath
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shotokka
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VishnAndr
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soheil_st
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berkaydurmaz
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mvaibhav
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Rupesh_Kumar25
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Dan_Wroblewski
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Dan_Wroblewski
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Developer Advocate

@SachinArtani I think DJ is looking for the RFC number only, let's say "123" and not "RFC123", which is what I think you hashed.

@qmacro There are 2 RFCs that I found that might be relevant, lets call them A and B. In Capire, A is mentioned, and I am assuming the one you want. But I have seen on the web this article where it says that A is outdated and we now use B.


"GUIDs are defined by IETF standards (RFCs). For many years, developers referenced RFC A (published July 2005), but this document has been formally obsoleted by RFC B (published May 2024). 

Since you wrote what is the CAP UUID compliant with, I assume we have to go with A, since technically that is what CAP is promising.

 

SergioG_TX
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Chaimae_Chairi27
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parthasaradhi
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Joery
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Caisi
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MioYasutake
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henry-collins1
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The relevant RFC wasn't too hard to track down once I looked into the UUID specification. Just remember that the challenge requires submitting the answer as a hash, not posting the RFC number directly.

NakulG
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lidavidlee
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kasch-code
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ajmaradiaga
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AndriiDanilishin
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NakulG
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Laco
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henry-collins1
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A good place to start is checking the CAP documentation for the UUID built-in type and then following the referenced RFC. The answer is there once you trace the specification.

MatLakaemper
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