Mike, I'm afraid the maximum total length needed is even longer than 38 characters (which is the maximum length of bignum). The article, which Jim refers to, contains the statement you need a 128 bit integer.
Tony -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mike Byerley Sent: donderdag 2 mei 2013 15:43 To: RBASE-L Mailing List Subject: [RBASE-L] - Re: European IBAN (International Bank Account Number) check digit calculation Or a 64 bit integer. ----- Original Message ----- From: "James Bentley" <[email protected]> To: "RBASE-L Mailing List" <[email protected]> Sent: Thursday, May 02, 2013 5:36 AM Subject: [RBASE-L] - Re: European IBAN (International Bank Account Number) check digit calculation Tony, The following Wikipedia article has a section on computing the mod if a computer language cannot handle 30 digit integers. http://en.wikipedia.org/wiki/International_Bank_Account_Number Per RBase V9.1 64 bit or V9.5 64 bit documentation, the BIGNUM data type can hold the derived integer. >From the Wikipedia article you can enter set var d bignum (30,0) = 3214282912345698765432161182 Show var: Variable = Value Type -------------------- ------------------------------ ------- #DATE = 05/02/2013 DATE #TIME = 4:14:02 TIME #PI = 3.14159265358979 DOUBLE SQLCODE = 0 INTEGER SQLSTATE = 00000 TEXT #NOW = 05/02/2013 4:14:02 DATETIME d = 3214282912345698765432161182 BIGNUM (30, 0) you are correct that the mod function does not handle BIGNUM as a valid data type R>set var dy integer = (mod(.d,97)) -ERROR- Unrecognized command - retype it ( 40) Certainly, an enhancement request to add BIGNUM as acceptable argument for MOD function would be in order. In the meantime you could used the method described in the Wikipedia article to create a Stored Procedure (function) to process the number in parts. Jim Bentley, American Celiac Society 1-504-737-3293 ________________________________ From: Tony IJntema <[email protected]> To: RBASE-L Mailing List <[email protected]> Sent: Thursday, May 2, 2013 2:20 AM Subject: [RBASE-L] - European IBAN (International Bank Account Number) check digit calculation Hi, In 2014 we will have to use a new bank account number in Europe. It looks like this: NL91ABNA0417164300 91 is a check digit This check digit is a result of a mod 97 operation. The calculation that needs to be performed is: (mod(101123100417164300232100,97)) (The length of the figure is 24 characters) The result = 7 The check digit then becomes 98 - 7 = 91 My question is: This figure is too big for a modular operation and bignums are not allowed in the mod function. Does anybody know a workaround? N.B. To rules to create the long figure are: Change the IBAN to: ABNA0417164300NL00 (Put NL (=countrycode) after the figure and add two zeroes to it. Replace all letters by it's position in the Alphabet and add 9 to this number ( A = 10, B = 11, and so on) Tony
