Everything was going fine until an update query failed. I then var_dumped the object and found out the class actually doesn't quote the values. The _lastQuery looked something like this.
UPDATE users_temp SET field1= value1,field2= ,field3 = value3 WHERE id = someinteger
Having empty value for field2 caues the query to look like above and failed. I expected the class to quote the values but apparently it doesn't. Checking every value for its emptiness seems a little extra work for me. So, is there any other arrangement in the class for this issue?