Bug #886: jdbc "update row" can mess up other columns - Mailing list pgsql-bugs

Andrew Fyfe (afyfe@bigtribe.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");
        }
        }
    }

    }
}


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