Re: Bug #886: jdbc "update row" can mess up other columns

Half of this bug was fixed at some point, but an exception is still thrown
when calling rs.afterLast() and then rs.previous(). Attached is a
regression test addition and the appropriate fix. Sorry for the extreme
delay in response and thanks for the thorough report.

Kris Jurka

On Fri, 24 Jan 2003 pgsql-bugs(at)postgresql(dot)org wrote:

> Andrew Fyfe (afyfe(at)bigtribe(dot)com) reports a bug with a severity of 3
> The lower the number the more severe it is.
>
> Short Description
> jdbc "update row" can mess up other columns
>
> Long Description
> The attached program when run gives me the following output
>
> DatabaseProductName: PostgreSQL
> DatabaseProductVersion: 7.3.1
> DriverName: PostgreSQL Native Driver
> DriverVersion: PostgreSQL 7.3.1 JDBC3 jdbc driver build 106
> --- Forward ---
> 1: Colombian 7.99
> 2: French_Roast 9.99
> --- Backward ---
> 2: French_Roast 9.99
> 1: Colombian 7.99
> --- Update Row 2 ---
> --- Forward ---
> 1: Colombian 7.99
> 2: Colombian 10.99
>
> Note that the update of the price in row 2 caused jdbc to misrepesent the name. If one does not run through the rows backward (give the arg "b" when running the code), then the output is correct:
>
> --- Forward ---
> 1: Colombian 7.99
> 2: French_Roast 9.99
> --- Update Row 2 ---
> --- Forward ---
> 1: Colombian 7.99
> 2: French_Roast 10.99
>
> Suppressing the first forward pass through the data (giving "f" or "fb" to suppress both) will cause an exception to be thrown.
>
> Note that another forward pass after the backward makes the problem go away.
>
> Sample Code
> import java.util.*;
> import java.sql.*;
>
> class pgbug
> {
> static String url = "jdbc:postgresql://localhost/cdb";
> static String driver = "org.postgresql.Driver";
> static String userName = "cdb";
> static String password = "cdb";
>
> public static void print(ResultSet rs) {
> try {
> String s = rs.getString("COF_NAME");
> float n = rs.getFloat("PRICE");
> int rowNum = rs.getRow();
> System.out.println(rowNum + ":\t" + s + "\t" + n);
> } catch (SQLException sqlEx) { /* ignore */
> System.out.println("print ResultSet failed");
> }
> }
>
> public static void forward(ResultSet rs) {
> try {
> System.out.println("--- Forward ---");
> rs.beforeFirst();
> while (rs.next()) {
> print(rs);
> }
> } catch (SQLException sqlEx) { /* ignore */
> System.out.println("print ResultSet failed");
> }
> }
>
> public static void backward(ResultSet rs) {
> try {
> System.out.println("--- Backward ---");
> rs.afterLast();
> while (rs.previous()) {
> print(rs);
> }
> } catch (SQLException sqlEx) { /* ignore */
> System.out.println("print ResultSet failed");
> }
> }
>
> public static void main(String args [])
> throws Exception
> {
>
> Connection conn = null;
> Statement stmt = null;
>
> try {
> // Load the mysql JDBC driver
> Class.forName(driver).newInstance();
>
> // Connect to the database
> Properties props = new Properties();
> props.put("user", userName);
> props.put("password", password);
> props.put("loglevel", "0");
> conn = DriverManager.getConnection(url, props);
>
> // Create a Statement
> stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
> ResultSet.CONCUR_UPDATABLE);
>
> DatabaseMetaData meta = conn.getMetaData();
> System.out.println("DatabaseProductName: " +
> meta.getDatabaseProductName());
> System.out.println("DatabaseProductVersion: " +
> meta.getDatabaseProductVersion());
> System.out.println("DriverName: " +
> meta.getDriverName());
> System.out.println("DriverVersion: " +
> meta.getDriverVersion());
>
> try {
> stmt.executeUpdate("drop table coffees");
> } catch (SQLException sqlEx) { /* ignore */
> System.out.println("drop table failed");
> }
>
> // create the table
> String createTableCoffees = "create table coffees " +
> "(COF_NAME VARCHAR(32) primary key, PRICE FLOAT)";
> try {
> stmt.executeUpdate(createTableCoffees);
> } catch (SQLException sqlEx) { /* ignore */
> System.out.println("create table failed");
> }
>
> stmt.executeUpdate("insert into coffees " +
> "VALUES ('Colombian', 7.99)");
> stmt.executeUpdate("insert into coffees " +
> "VALUES ('French_Roast', 9.99)");
>
> // Select from the test table
> String query = "select cof_name, price from coffees";
> ResultSet rs = stmt.executeQuery(query);
>
> if (args.length == 0 || args[0].indexOf('f') < 0) {
> forward(rs);
> }
> if (args.length == 0 || args[0].indexOf('b') < 0) {
> backward(rs);
> }
>
> if (rs.absolute(2)) {
> System.out.println("--- Update Row 2 ---");
> rs.updateFloat("PRICE", 10.99f);
> rs.updateRow();
> }
>
> forward(rs);
> } finally {
> if (stmt != null) {
> try {
> stmt.close();
> }
> catch (SQLException sqlEx) {
> System.out.println("closing statement failed");
> }
> }
> if (conn != null) {
> try {
> conn.close();
> }
> catch (SQLException sqlEx) {
> System.out.println("closing connection failed");
> }
> }
> }
>
> }
> }
>
>
> No file was uploaded with this report
>
>
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