Conditional Operators

Given the following code ....

string sVal = (reader.IsDBNull(i)) ? "null" : ObjectToSQLString(objs[i]);

        static string ObjectToSQLString(object o)
        {
            if (o == null || o == DBNull.Value)
                return "null";

            Type t = o.GetType();

            if (t == typeof(string))
                return string.Format("'{0}'", ((string)o).Trim().Replace("'", "''"));
            if (t == typeof(int))
                return ((int)o).ToString();
            if (t == typeof(Int16))
                return ((Int16)o).ToString();
            if (t == typeof(long))
                return ((long)o).ToString();
            if (t == typeof(float))
                return ((float)o).ToString();
            if (t == typeof(double))
                return ((double)o).ToString();
            if (t == typeof(bool))
                return ((bool)o).ToString();
            if (t == typeof(DateTime))
                return string.Format("'{0}'", ((DateTime)o));

            throw new DataException();
        }

any chance of an explanation of the line

string sVal = (reader.IsDBNull(i)) ? "null" : ObjectToSQLString(objs[i]);

Thanks