[JENA-1939] getUpdateCount() in the JDBC driver returns incorrect value - it looks like there are always more results (infinite loop)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Jena 3.17.0
• Component/s: JDBC
• Flags: Patch
• Assignee: Rob Vesse
• Reporter: František Kučera
• Created: 25/Jul/20 11:21
• Updated: 01/Dec/20 14:32
• Resolved: 17/Aug/20 09:10

Description

The method JenaStatement.getUpdateCount() returns 0. But java.sql.Statement documentation says:

Returns: the current result as an update count; -1 if the current result is a ResultSet object or there are no more results

Returning correct value is important because a single statement may have multiple result sets and cause mutiple updates (not only multiple updated records, but multiple sets of updated records).

Applications (e.g. SQL-DK) iterate over these multiple results and need to know when finish. The getMoreResults() documentation says:

There are no more results when the following is true: ((stmt.getMoreResults() == false) && (stmt.getUpdateCount() == -1))

But if 0 is returned, the application enters infinite loop.

I think that change in my branch could resolve this issue (also attached as a patch).

P.S. Is there a way to return actual count of updated records? (UpdateProcessor.execute() returns void).