Обсуждение: Statement.ececuteUpdate() closes ResultSet obtained from same Statement

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Statement.ececuteUpdate() closes ResultSet obtained from same Statement

От
Christian Schlichtherle
Дата:
I am not sure if this is a bug or a feature, but here it goes:

package cpssd.postgresql;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.sql.*;

public class TicketIT {
   private static Connection getConnection() throws SQLException {       return DriverManager.getConnection("jdbc:postgresql:postgres");   }
   @Before   public void createTable() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           s.executeUpdate("CREATE TABLE test(a INT)");       }   }
   @After   public void dropTable() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           s.executeUpdate("DROP TABLE test");       }   }
   @Test(expected = SQLException.class)   public void testSharedStatementClosesResultSet() throws SQLException {       try (Connection c = getConnection();            Statement s = c.createStatement()) {           try (ResultSet rs = s.executeQuery("SELECT a FROM test")) {               s.executeUpdate("INSERT INTO test(a) VALUES (1)");               // Expected false, but throws SQLException: This statement has been closed.               assert !rs.next();           }       }   }
   @Test   public void testUsingAnotherStatementWorks() throws SQLException {       try (Connection c = getConnection();            Statement s1 = c.createStatement()) {           try (ResultSet rs = s1.executeQuery("SELECT a FROM test")) {               try (Statement s2 = c.createStatement()) {                   s2.executeUpdate("INSERT INTO test(a) VALUES (1)");               }               assert !rs.next();           }       }   }
}


Вложения

Re: Statement.ececuteUpdate() closes ResultSet obtained from same Statement

От
David G Johnston
Дата:
christian wrote
> I am not sure if this is a bug or a feature

Feature. Use one statement for each query you need active simultaneously.

David J.



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Re: Statement.ececuteUpdate() closes ResultSet obtained from same Statement

От
Glenn Holmer
Дата:
On 08/24/2014 07:33 AM, Christian Schlichtherle wrote:
> I am not sure if this is a bug or a feature, but here it goes:
>     @Test(expected = SQLException.class)
>     public void testSharedStatementClosesResultSet() throws SQLException {
>         try (Connection c = getConnection();
>              Statement s = c.createStatement()) {
>             try (ResultSet rs = s.executeQuery("SELECT a FROM test")) {
>                 s.executeUpdate("INSERT INTO test(a) VALUES (1)");
>                 // Expected false, but throws SQLException: This statement has been closed.
>                 assert !rs.next();
>             }
>         }
>     }

http://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html

"All execution methods in the Statement interface implicitly close a
statment's current ResultSet object if an open one exists."

--
Glenn Holmer (Linux registered user #16682)
"After the vintage season came the aftermath -- and Cenbe."