Data commit

Task/Validate-International-Securities-Identification-Number/Transact-SQL/validate-international-securities-identification-number-1.sql

@@ -0,0 +1,41 @@
+CREATE FUNCTION dbo._ISINCheck( @strISIN VarChar(40) )
+RETURNS bit
+AS
+BEGIN
+--*** Test an ISIN code and return 1 if it is valid, 0 if invalid.
+DECLARE @bValid	 bit;
+
+SET @bValid = CASE WHEN @strISIN LIKE '[A-Z][A-Z][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][A-Z,0-9][0-9]' THEN 1 ELSE 0 END
+IF @bValid = 1
+	BEGIN
+		DECLARE @strTest VarChar(40) = '';
+		DECLARE @strAdd  VarChar(2);
+		DECLARE @p INT = 0;
+		WHILE @p < LEN(@strISIN)
+			BEGIN
+				SET @p = @p+1;
+				SET @strAdd = SUBSTRING(@strISIN,@p,1);
+				IF @strAdd LIKE '[A-Z]' SET @strAdd = CONVERT(VarChar(2),ASCII(UPPER(@strAdd))-55);
+				SET @strTest = @strTest + @strAdd;
+			END;
+
+		-- Proceed with Luhn test
+		DECLARE @strLuhn VarChar(40) = REVERSE(@strTest); -- usage: set once, never changed
+		DECLARE @strS2Values VarChar(10) = '0246813579';  -- constant: maps digits to their S2 summed values
+		SET @p = 0; -- reset loop counter
+		DECLARE @intValue INT;
+		DECLARE @intSum	INT = 0;
+		-- loop through the reversed string, get the value (even-positioned digits are mapped) and add it to @intSum
+		WHILE @p < LEN(@strLuhn)
+			BEGIN
+				SET @p = @p+1;
+				SET @intValue = CONVERT(INT, SUBSTRING(@strLuhn,@p,1) ) -- value of the digit at position @p in the string
+				IF @p % 2 = 0	SET @intValue = CONVERT(INT,SUBSTRING(@strS2Values,@intValue+1,1))
+				SET @intSum = @intSum + @intValue
+			END
+		-- If the of the digits' mapped values ends in 0 (modulo 10 = 0) then the Luhn test succeeds
+		SET @bValid = CASE WHEN @intSum % 10 = 0 THEN 1 ELSE 0 END
+	END;
+
+RETURN @bValid
+END

Task/Validate-International-Securities-Identification-Number/Transact-SQL/validate-international-securities-identification-number-2.sql

@@ -0,0 +1,13 @@
+-- Testing. The following tests all pass.
+;WITH ISIN_Tests AS
+( SELECT 'US0378331005' AS ISIN, 1 Expected
+  UNION SELECT 'US0373831005',0
+  UNION SELECT 'U50378331005',0
+  UNION SELECT 'US03378331005',0
+  UNION SELECT 'AU0000XVGZA3',1
+  UNION SELECT 'AU0000VXGZA3',1
+  UNION SELECT 'FR0000988040',1
+  UNION SELECT '0___garbage',0
+  UNION SELECT '',0
+)
+SELECT ISIN, Expected, dbo._ISINCheck(ISIN) AS TestResult FROM ISIN_Tests ORDER BY ISIN