I'm a little concerned that this issue seems to be withering on the vine
so to speak so I thought I would bring it back to the attention of the
dev list again.
In an effort to collect more information I have been running simple
tests such as the one I've attached to this email against db2, oracle
and mysql. The JDBC 4.0 specifications state that a ResultSet will close
"if the cursor is forward only, then when invocation of its next method
returns
false". Yet none of the Databases I've tested do this, including Derby
Embedded. The only test to follow this behavior I've found was Derby
Client and this way have played some part in the SQuirreL malfunction
mentioned earlier.
So will JDBC 4.0 "break" these drivers in this respect or is there some
other resolution?
On a related note would anyone find it beneficial if I were to collect
this thread into one document and posted it to the newsgroup? This issue
has gone on for some time now and I can understand if anyone is having
trouble following the thread.
Philip
Dan Debrunner wrote:
Kathey Marsden wrote:
Lance J. Andersen wrote:
I am just getting back from J1 and I have a quite a few emails to wade
through. If/when you hace a cycle, if you can summarize the issues
outstanding, i can look at it and discuss with the EG. There are sooo
many emails from derby-dev, it is going to take me quite some time to
digest it all.
Hi Lance,
Yes, there is a lot of mail. At least this thread would be worth
reading in its entirety. The executive summary as Philip would put it
is that
Regarding the spec, the biggest items resolve to me seem to me to be.
- When is a result set closed and when should next return false vs
throw an exception?
I think it is well defined when a result set is closed, I think it's
more once it is closed, what should its methods do? Especially
rs.next(), return false or throw an exception. At least, for Lance & the
EG, I think we need a better question than "when is a result set closed'.
Dan.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class SimpleResultSetTest {
public static void main(String[] args) {
try {
//Change based on the database in use
final String driver = "com.mysql.jdbc.Driver";
final String protocol = "jdbc:mysql://localhost:3306/testDB";
final String username = "root";
final String password = "password";
Class.forName(driver).newInstance();
Connection conn = null;
Properties props = new Properties();
props.put("user", username);
props.put("password", password);
conn = DriverManager.getConnection(protocol, props);
Statement s = conn.createStatement(ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_READ_ONLY);
try {
s.executeUpdate("create table t1 (num int)");
} catch (SQLException e) {
//Table already exists, remove rows
s.executeUpdate("delete from t1");
}
s.executeUpdate("insert into t1 values (1)");
s.executeUpdate("insert into t1 values (2)");
ResultSet rs = s.executeQuery("select * from t1");
while (rs.next()) {
System.out.println(rs.getString(1));
}
try {
ResultSetMetaData rsmd = rs.getMetaData();
System.out.println(rsmd.getColumnCount());
System.out.println(rs.next()); //No Exception yet
rs.close();
System.out.println(rs.next()); //Exception
} catch (SQLException e) {
e.printStackTrace();
}
rs.close();
s.executeUpdate("drop table t1");
s.close();
conn.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
