[DERBY-795] After calling ResultSet.relative(0) the cursor loses its position

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 10.1.2.1, 10.2.1.6
• Fix Version/s: 10.1.3.1, 10.2.1.6
• Component/s: JDBC
• Environment: Any
• Issue & fix info: Patch Available
• Assignee: Andreas Korneliussen
• Reporter: Andreas Korneliussen
• Created: 04/Jan/06 22:11
• Updated: 10/May/06 19:34
• Resolved: 10/May/06 19:34

Description

After calling rs.relative(0), on a scrollable ResultSet, the cursor looses its position, and a rs.getXXX(..) fails with:
SQL Exception: Invalid cursor state - no current row.

Probably caused by the following logic in ScrollInsensitiveResultSet.getRelativeRow(int row):
// Return the current row for 0
if (row == 0)
{
if ((beforeFirst || afterLast) ||
(!beforeFirst && !afterLast))

{ return null; }

else

{ return getRowFromHashTable(currentPosition); }

}

The if () will always evaluate to true, regardless of the values of beforeFirst and afterLast

Test code:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class RelativeZeroIssue {

public static void main(String[] args) throws Exception {

Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
Connection con = DriverManager.getConnection("jdbc:derby:testdb2;create=true");
con.setAutoCommit(false);
try

{ Statement statement = con.createStatement(); /** Create the table */ statement.execute("create table t1(id int)"); statement.execute("insert into t1 values 1,2,3,4,5,6,7,8"); Statement s = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); ResultSet rs = s.executeQuery("select * from t1"); rs.next(); System.out.println(rs.getInt(1)); System.out.println(rs.relative(0)); System.out.println(rs.getInt(1)); }

finally

{ con.rollback(); con.close(); }

}

}

Output from test:
1
false
Exception in thread "main" SQL Exception: Invalid cursor state - no current row.
at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection.newSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.ConnectionChild.newSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedResultSet.checkOnRow(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedResultSet.getColumn(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedResultSet.getInt(Unknown Source)
at derbytest.RelativeZeroIssue.main(RelativeZeroIssue.java:51)
Java Result: 1