Requirements of getMoreResults()/getMoreResults(int)

[Mark Rotteveel]

I just ran into a question on stackoverflow, 
http://stackoverflow.com/q/33853354/466862 about the requirements for 
getMoreResults() vs getMoreResults(int).

The description of getMoreResults() says:

"and implicitly closes any current ResultSet object(s) obtained with the 
method getResultSet."

As it uses **any** and object**(s)**, this sounds to me like its 
behavior should be the equivalent of 
getMoreResults(Statement.CLOSE_ALL_RESULTS), however getMoreResults(int) 
says:

"SQLFeatureNotSupportedException - if 
DatabaseMetaData.supportsMultipleOpenResults returns false and either 
Statement.KEEP_CURRENT_RESULT or Statement.CLOSE_ALL_RESULTS are 
supplied as the argument."

This was added in JDBC 4, JDBC 3 had no such requirement.

So, what is the required behavior for getMoreResults()? Is it always 
getMoreResults(Statement.CLOSE_CURRENT_RESULT), or is it 
getMoreResults(Statement.CLOSE_CURRENT_RESULT) in a driver that does not 
support multiple results, and 
getMoreResults(Statement.CLOSE_ALL_RESULTS) in a driver that does 
support multiple open results?

If the second, then I think for a driver that does not support multiple 
open results this distinction is unnecessary, because then closing the 
current result is the same as closing all results (as there is only one 
open result); and then the requirement to throw 
SQLFeatureNotSupportedException for Statement.CLOSE_ALL_RESULTS is also 
unnecessary.

On a related note, the DatabaseMetData.supportsMultipleOpenResults says:

"Retrieves whether it is possible to have multiple ResultSet objects 
returned from a CallableStatement object simultaneously."

I think CallableStatement should be changed to Statement as you can call 
stored procedures (or other statements) that have multiple results also 
with Statement or PreparedStatement.

Mark Rotteveel
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Mark Rotteveel