Decimal byte array constructor requires an array of length four containing valid decimal bytes.

This error was very surprising for me. I spent couple of hours with my friends and even search a lot on internet to quikly fix this problem but I could not solved.
Finally I asked one of my senior and he fixed it in a second because he has faced this issue before.
Scenario: I wrote a query which consists of a column returning value like

select avg(tat) from employee.

It was returning values like

12.397339

2.00303

12.9800122

Note: This query was running perfectly in TOAD, SQL Developer while executed at Oracle Server.

When I executed the query in .Net and bind the result to the dataset, i started getting the above exception. I was so much frustrated why it is not executed in .Net when in Oracle the same query is executed.

Reason: Dataset does not support the binding of a value having more than 2 decimal places. So I have to round the values to two decimal places.

Solution: select round(avg(tat),2) from employee

Note: You might also get the message as Accessor is not a parameter accessor.

The reason if the same what I discussed here.