Create a unique random number in Dynamics Ax x++

static void JobEF_RandomNumber(Args _args)
{
    System.Random rand = new System.Random();
    MYTable MYTable;
    int value = rand.Next();
    boolean found;

    info(strFmt('%1', value));
    
    while (!found)
    {
        value = rand.Next(10);
        if ((select firstOnly MYTable where MYTable.ChangeRequestId == value).RecId == 0)
            found = true;
    }
    

    info(strFmt('%1', value));
}