What is the use of derived properties in Hibernate ?

The derived properties don't appear in INSERT statements.

Derived properties do not represent any real column.

Every time a SELECT statement is executed, the derived properties will get calculated according to the formula defined.

Example

<property name="averageBidAmount" 

 formula="(select AVG(b.AMOUNT) from BID b where b.ITEM_ID=ITEM_ID )"

 type="big_decimal" />