Thread: jdbc / getTables bug?
Is anyone aware of a problem in the jdbc driver for the getTables()
function when a view is present? I'm getting a null pointer exception:
Exception caught.
java.lang.NullPointerException
java.lang.NullPointerException
at
org.postgresql.jdbc2.DatabaseMetaData.getTables(DatabaseMetaData.java:1707)
at mettst.doDatabaseMetaData(mettst.java:20)
at mettst.<init>(mettst.java:73)
at mettst.main(mettst.java:126)
I'm using Postgresql version 7.1 and 7.1.2 and this occurs in both. This
exception only occurs if a view is present.
Here's the complete java code to reproduce this (this problem was
encountered when I ran the metadata example that came with the jdbc dirver
code was run against my database. I narrowed down a test for this problem
using this example). Any ideas?
Thanks.
---------------------------- 8< -----------------------------8<
-----------------------------
import java.io.*;
import java.sql.*;
import java.text.*;
/**
* Test jdbc view bug
* To use it, simply have a database created. It will create some work tables
* and run tests on them.
*/
public class mettst
{
Connection db; // The connection to the database
Statement st; // Our statement to run queries with
DatabaseMetaData dbmd; // This defines the structure of the database
public void doDatabaseMetaData() throws SQLException {
displayResult(dbmd.getTables(null,null,null,null));
}
public void init() throws SQLException {
System.out.println("Creating tables and view");
cleanup();
st.executeUpdate("create table x " +
"(col1 text);");
st.executeUpdate("create view vx as " +
"select col1 " +
"from x;");
}
public void cleanup() throws SQLException {
System.out.println("Cleaning up...");
try {
st.executeUpdate("drop table x;");
} catch(Exception ex) {
// ignore any errors here
}
try {
st.executeUpdate("drop view vx;");
} catch(Exception ex) {
// ignore any errors here
}
}
public mettst() throws ClassNotFoundException, FileNotFoundException,
IOException, SQLException
{
String url = "jdbc:postgresql://derby:5432/mettst";
String usr = "user1";
String pwd = "";
// Load the driver
Class.forName("org.postgresql.Driver");
// Connect to database
System.out.println("Connecting to Database URL = " + url);
db = DriverManager.getConnection(url, usr, pwd);
System.out.println("getMetaData()");
dbmd = db.getMetaData();
st = db.createStatement();
// This prints the backend's version
System.out.println("Connected to "+dbmd.getDatabaseProductName()+"
"+dbmd.getDatabaseProductVersion());
init();
System.out.println("Now the test...");
// Now the test
doDatabaseMetaData();
System.out.println("\nNow closing the connection");
st.close();
db.close();
cleanup();
}
/**
* This displays a result set.
* Note: it closes the result once complete.
*/
public void displayResult(ResultSet rs) throws SQLException
{
System.out.println("Dispay ResultSet");
ResultSetMetaData rsmd = rs.getMetaData();
int count=0;
// Print the result column names
int cols = rsmd.getColumnCount();
for(int i=1;i<=cols;i++)
System.out.print(rsmd.getColumnLabel(i)+(i<cols?"\t":"\n"));
// now the results
while(rs.next()) {
count++;
for(int i=1;i<=cols;i++) {
Object o = rs.getObject(i);
if(rs.wasNull())
System.out.print("{null}"+(i<cols?"\t":"\n"));
else
System.out.print(o.toString()+(i<cols?"\t":"\n"));
}
}
System.out.println("Result returned "+count+" rows.");
// finally close the result set
rs.close();
}
public static void main(String args[])
{
System.out.println("PostgreSQL metdata tester v6.4 rev 1\n");
// This line outputs debug information to stderr. To enable this, simply
// add a parameter to the command line
if(args.length>0)
DriverManager.setLogStream(System.err);
// Now run the tests
try {
mettst test = new mettst();
} catch(Exception ex) {
System.err.println("Exception caught.\n"+ex);
ex.printStackTrace();
}
}
}
Laurette Cisneros
NextBus Information Systems
laurette@nextbus.com
(510) 420-3137
Why wait?
www.nextbus.com
Yes, this is a known problem and I believe has been fixed in cvs. If you
want you can pick up the jars from jdbc.fastcrypt.com
Dave
----- Original Message -----
From: "Laurette Cisneros" <laurette@nextbus.com>
To: <pgsql-jdbc@postgresql.org>
Sent: Monday, June 18, 2001 3:04 PM
Subject: [JDBC] jdbc / getTables bug?
> Is anyone aware of a problem in the jdbc driver for the getTables()
> function when a view is present? I'm getting a null pointer exception:
> Exception caught.
> java.lang.NullPointerException
> java.lang.NullPointerException
> at
>
org.postgresql.jdbc2.DatabaseMetaData.getTables(DatabaseMetaData.java:1707)
> at mettst.doDatabaseMetaData(mettst.java:20)
> at mettst.<init>(mettst.java:73)
> at mettst.main(mettst.java:126)
>
> I'm using Postgresql version 7.1 and 7.1.2 and this occurs in both. This
> exception only occurs if a view is present.
>
> Here's the complete java code to reproduce this (this problem was
> encountered when I ran the metadata example that came with the jdbc dirver
> code was run against my database. I narrowed down a test for this problem
> using this example). Any ideas?
>
> Thanks.
>
> ---------------------------- 8< -----------------------------8<
> -----------------------------
>
> import java.io.*;
> import java.sql.*;
> import java.text.*;
>
> /**
> * Test jdbc view bug
> * To use it, simply have a database created. It will create some work
tables
> * and run tests on them.
> */
>
> public class mettst
> {
> Connection db; // The connection to the database
> Statement st; // Our statement to run queries with
> DatabaseMetaData dbmd; // This defines the structure of the
database
>
> public void doDatabaseMetaData() throws SQLException {
>
> displayResult(dbmd.getTables(null,null,null,null));
>
> }
>
> public void init() throws SQLException {
> System.out.println("Creating tables and view");
> cleanup();
> st.executeUpdate("create table x " +
> "(col1 text);");
> st.executeUpdate("create view vx as " +
> "select col1 " +
> "from x;");
> }
>
> public void cleanup() throws SQLException {
> System.out.println("Cleaning up...");
> try {
> st.executeUpdate("drop table x;");
> } catch(Exception ex) {
> // ignore any errors here
> }
> try {
> st.executeUpdate("drop view vx;");
> } catch(Exception ex) {
> // ignore any errors here
> }
> }
>
> public mettst() throws ClassNotFoundException, FileNotFoundException,
> IOException, SQLException
> {
> String url = "jdbc:postgresql://derby:5432/mettst";
> String usr = "user1";
> String pwd = "";
>
> // Load the driver
> Class.forName("org.postgresql.Driver");
>
> // Connect to database
> System.out.println("Connecting to Database URL = " + url);
> db = DriverManager.getConnection(url, usr, pwd);
>
> System.out.println("getMetaData()");
> dbmd = db.getMetaData();
> st = db.createStatement();
>
> // This prints the backend's version
> System.out.println("Connected to "+dbmd.getDatabaseProductName()+"
> "+dbmd.getDatabaseProductVersion());
>
> init();
>
> System.out.println("Now the test...");
>
> // Now the test
> doDatabaseMetaData();
>
> System.out.println("\nNow closing the connection");
> st.close();
> db.close();
>
> cleanup();
> }
>
> /**
> * This displays a result set.
> * Note: it closes the result once complete.
> */
> public void displayResult(ResultSet rs) throws SQLException
> {
> System.out.println("Dispay ResultSet");
> ResultSetMetaData rsmd = rs.getMetaData();
> int count=0;
>
> // Print the result column names
> int cols = rsmd.getColumnCount();
> for(int i=1;i<=cols;i++)
> System.out.print(rsmd.getColumnLabel(i)+(i<cols?"\t":"\n"));
>
> // now the results
> while(rs.next()) {
> count++;
> for(int i=1;i<=cols;i++) {
> Object o = rs.getObject(i);
> if(rs.wasNull())
> System.out.print("{null}"+(i<cols?"\t":"\n"));
> else
> System.out.print(o.toString()+(i<cols?"\t":"\n"));
> }
> }
>
> System.out.println("Result returned "+count+" rows.");
>
> // finally close the result set
> rs.close();
> }
>
> public static void main(String args[])
> {
> System.out.println("PostgreSQL metdata tester v6.4 rev 1\n");
>
> // This line outputs debug information to stderr. To enable this,
simply
> // add a parameter to the command line
> if(args.length>0)
> DriverManager.setLogStream(System.err);
>
> // Now run the tests
> try {
> mettst test = new mettst();
> } catch(Exception ex) {
> System.err.println("Exception caught.\n"+ex);
> ex.printStackTrace();
> }
> }
> }
>
>
> Laurette Cisneros
> NextBus Information Systems
> laurette@nextbus.com
> (510) 420-3137
> Why wait?
> www.nextbus.com
>
>
>
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