[hibernate-dev] criteria + SUM

[Emmanuel Bernard]

We fail because we return Long and not Integer, correct?

That's one of the latest changes we did in the spec (the addition of the sumAsLong / sumAsDouble, especially for the case where you sum two integers.

"
>> We will add the following 2 methods to the QueryBuilder(now CriteriaBuilder)
>>    interface to support the JPQL semantics of returning Long when integers are
>>    summed and Double when floats are summed:

"

It looks like the spec has a bug, while the TCK is correct.
You can challenge the TCK but if the TCK test does sum two integers and return an integer, that's the intend of the spec commitee and I would rather get us follow this line.

Emmanuel


On 7 janv. 2010, at 16:27, Steve Ebersole wrote:

> My understanding is that the return types for aggregation function in
> criteria queries should follow the same rules as defined for JPAQL.  So
> first, is that a correct understanding?
> 
> The confusion is the type signatures of the builder methods, espcially
> the ones that "change" based on the argument types.  SUM, for example,
> says the following in the JPAQL section:
> <quote>
> SUM returns Long when applied to state fields of integral types (other
> than BigInteger); Double
> when applied to state fields of floating point types; BigInteger when
> applied to state fields
> of type BigInteger; and BigDecimal when applied to state fields of type
> BigDecimal.
> </quote>
> 
> So for a SUM of int or Integer fileds, JPAQL is clearly expecting back a
> Long.
> 
> The CriteriaBuilder sum method, however, is defined as:
> <N extends Number> Expression<N> sum(Expression<N> x);
> 
> Which implies that when applied to an int or Integer field/expression
> should return an Integer.  Yes, I realize the last spec version added
> the sumAsDouble/sumAsLong methods, but that is still not really the same
> as the JPAQL rules.
> 
> The TCK does explicitly have a test for this btw and we are currently
> failing.  *However* even the test notes show the confusion here as it
> states:
> <quote>
> Execute a query which contains the aggregate function SUM.
> SUM returns Long when applied to state-fields of integral types.
> </quote>
> 
> Unfortunately as soon as it says that is goes off and actually asserts
> the return is a Integer ;)
> 
> So I am trying to decide if this need be a challenge based on "alignment
> with JPAQL rules", a challenge based on something else you might see or
> an inconsistency JPA users will have to live with?
> 
> -- 
> Steve Ebersole <steve at hibernate.org>
> Hibernate.org
>