using System;

namespace DB2ClassLibrary
{
	/// <summary>
	/// Summary description for DB2Class1.
	/// This class and method can be used as the basis for a DB2 CLR procedure.
	/// </summary>
	public class DB2Test
	{
		public static void SamDurak(Double inOperand1, Double inOperand2, out Double outResult, Int16 operand1NullInd, Int16 operand2NullInd, out Int16 outResultNullInd, ref String sqlState, String funcName, String specName, ref String diagMsg, Int32 callType)
		{
			outResultNullInd =  0 ;
			outResult = inOperand1 + inOperand2;
		}
	}
}

Положил dll-ку в подкаталог FUNCTION, создал потом функцию:

CREATE FUNCTION S(REAL, REAL)
RETURNS REAL
EXTERNAL NAME 'DB2ClassLibrary.dll:DB2ClassLibrary.DB2Test!SamDurak'
LANGUAGE CLR
PARAMETER STYLE SQL
DETERMINISTIC
FENCED
THREADSAFE
NO SCRATCHPAD
EXECUTION CONTROL SAFE
ALLOW PARALLEL
NO DBINFO
FINAL CALL

using System;
using System.Text;
using System.Security.Cryptography;

namespace Tools.Encryption
{
	public class encrypting
	{
		public static string MD5(string password) {
			byte[] textBytes = System.Text.Encoding.Default.GetBytes(password);
			try {
				System.Security.Cryptography.MD5CryptoServiceProvider cryptHandler;
				cryptHandler = new System.Security.Cryptography.MD5CryptoServiceProvider();
				byte[] hash = cryptHandler.ComputeHash(textBytes);
				string ret = "";
				foreach (byte a in hash) {
					if (a <  16 ) ret += "0" + a.ToString("x");
					else ret += a.ToString("x");
				}
				return ret;
			}
			catch {
				return "";
			}
		}
		public static void MD5(string password, out string encryptedpassword, Int16 passwordNullInd, out Int16 encryptedpasswordNullInd)
		{
			if (passwordNullInd == - 1 )
			{
				encryptedpasswordNullInd = - 1 ;
				encryptedpassword = "";
			}
			else
			{
				encryptedpasswordNullInd =  0 ;
				encryptedpassword = MD5(password);
			}
		}
	}
}

CREATE FUNCTION MD5(VARCHAR( 30 ))
RETURNS VARCHAR( 16 ) FOR BIT DATA
EXTERNAL NAME 'Tools.Encryption.encrypting!MD5'
FENCED THREADSAFE RETURNS NULL ON NULL INPUT
DETERMINISTIC NO SQL NO EXTERNAL ACTION
LANGUAGE CLR PARAMETER STYLE SQL ALLOW PARALLEL;