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Maximum length rfc 4122 version 4

I see http://www.ietf.org/rfc/rfc4122.txt

What is the maximum length of RFC 4122 version 4? In other words, is the maximum length always the same as the approximate value of a string taken from a document? f81d4fae-7dec-11d0-a765-00a0c91e6bf6

I think the answer lies in the section that says: "The formal definition of the string representation of the UUID is provided by the following ABNF"

I needed a second opinion for the sake of a database table column (varchar).

Thank!

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1 answer

According to RFC 4122 :

The UUID is 128 bits long and can guarantee uniqueness in space and time.

, ABNF:

  UUID                   = time-low "-" time-mid "-"
                           time-high-and-version "-"
                           clock-seq-and-reserved
                           clock-seq-low "-" node
  time-low               = 4hexOctet
  time-mid               = 2hexOctet
  time-high-and-version  = 2hexOctet
  clock-seq-and-reserved = hexOctet
  clock-seq-low          = hexOctet
  node                   = 6hexOctet
  hexOctet               = hexDigit hexDigit
  hexDigit =
        "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" /
        "a" / "b" / "c" / "d" / "e" / "f" /
        "A" / "B" / "C" / "D" / "E" / "F"

16 hexOctet. 2 hexOctet 4 ( "-" ). 16 * 2 + 4 = 36 .

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