SequenceValueExtractor.queryString is defined as the following for all dialects except Derby:

"select currval('" + sequenceName + "');"

This is not the proper string for DB2, Oracle, or SQL Server and causes the following tests to fail:

• org.hibernate.id.SequenceHiLoGeneratorNoIncrementTest.testHiLoAlgorithm
• org.hibernate.id.SequenceHiLoGeneratorTest.testHiLoAlgorithm

It appears that the only those tests actually use SequenceValueExtractor. Is SequenceValueExtractor dead code? Should some other class be used in the tests?