[hibernate-dev] Multiple ResultSets from JDBC execution

[Steve Ebersole]

Execution of procedure calls, function calls and anonymous blocks can all
lead to JDBC returning us multiple ResultSets.

To account for this (for the first 2 anyway) JPA allows defining multiple
ResultSetMapping references for the StoredProcesdureQuery.  Alternatively,
it allows specifying multiple "result classes".  However, JPA is silently
on how a provider is to treat these.  Specifically, are these  "aggregated"
into a single "row reader"?  Or do they represent individual row readers
specific to each expected ResultSet?  In other words, are the ResultSets
heterogeneous or homogeneous?

At the moment, Hibernate treats these by building a single aggregated row
reader that it applies to reading all ResultSets.  Like I said, JPA is
silent on what this "means" (and the TCK does not test it) so we are free
to interpret this as we see fit.

In retrospect I think the multiple ResultSetMappping case is probably best
interpreted using the "distinct row reader per ResultSet" approach.  I'm
not so convinced that is always the best interpretation of the multiple
result classes case.  But I also think these should probably be handled
consistently.

So what is everybody's preference here?  Which interpretation do we pick?
Worth it to make this configurable (per-SF + per-Query)?