MySQLBackup.net works fine on Windows applications, but not in Xamarin (tested with exact same code).
Is there any workaround or alternatives that I can use ? I'm really lost...
I want to backup my database from a Linux (Debian9) MariaDB server, so I found MySqlBackup.NET, but nothing can make it work with Xamarin.
There's my code to backup (works in windows console app):
// Use MySqlBackup.Net to backup database
using (var conn = new MySqlConnection("myconnstring"))
{
conn.Open();
using (MySqlCommand cmd = new MySqlCommand())
{
conn.Open();
using (MySqlBackup mb = new MySqlBackup(cmd))
{
cmd.Connection = conn;
mb.ExportToFile(Constants.EXPORT_PATH + "/dolibarr_" + identifier + "dataBackup.sql");
conn.Close();
}
}
}
Getting exception: The type initializer for 'MySql.Data.MySqlClient.Replication.ReplicationManager' threw an exception.
How do you connect to a MySQL database in Java?
When I try, I get
java.sql.SQLException: No suitable driver found for jdbc:mysql://database/table
at java.sql.DriverManager.getConnection(DriverManager.java:689)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
Or
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
Or
java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver
Here's a step by step explanation how to install MySQL and JDBC and how to use it:
Download and install the MySQL server. Just do it the usual way. Remember the port number whenever you've changed it. It's by default 3306.
Download the JDBC driver and put in classpath, extract the ZIP file and put the containing JAR file in the classpath. The vendor-specific JDBC driver is a concrete implementation of the JDBC API (tutorial here).
If you're using an IDE like Eclipse or Netbeans, then you can add it to the classpath by adding the JAR file as Library to the Build Path in project's properties.
If you're doing it "plain vanilla" in the command console, then you need to specify the path to the JAR file in the -cp or -classpath argument when executing your Java application.
java -cp .;/path/to/mysql-connector.jar com.example.YourClass
The . is just there to add the current directory to the classpath as well so that it can locate com.example.YourClass and the ; is the classpath separator as it is in Windows. In Unix and clones : should be used.
Create a database in MySQL. Let's create a database javabase. You of course want World Domination, so let's use UTF-8 as well.
CREATE DATABASE javabase DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;
Create a user for Java and grant it access. Simply because using root is a bad practice.
CREATE USER 'java'#'localhost' IDENTIFIED BY 'password';
GRANT ALL ON javabase.* TO 'java'#'localhost' IDENTIFIED BY 'password';
Yes, java is the username and password is the password here.
Determine the JDBC URL. To connect the MySQL database using Java you need an JDBC URL in the following syntax:
jdbc:mysql://hostname:port/databasename
hostname: The hostname where MySQL server is installed. If it's installed at the same machine where you run the Java code, then you can just use localhost. It can also be an IP address like 127.0.0.1. If you encounter connectivity problems and using 127.0.0.1 instead of localhost solved it, then you've a problem in your network/DNS/hosts config.
port: The TCP/IP port where MySQL server listens on. This is by default 3306.
databasename: The name of the database you'd like to connect to. That's javabase.
So the final URL should look like:
jdbc:mysql://localhost:3306/javabase
Test the connection to MySQL using Java. Create a simple Java class with a main() method to test the connection.
String url = "jdbc:mysql://localhost:3306/javabase";
String username = "java";
String password = "password";
System.out.println("Connecting database...");
try (Connection connection = DriverManager.getConnection(url, username, password)) {
System.out.println("Database connected!");
} catch (SQLException e) {
throw new IllegalStateException("Cannot connect the database!", e);
}
If you get a SQLException: No suitable driver, then it means that either the JDBC driver wasn't autoloaded at all or that the JDBC URL is wrong (i.e. it wasn't recognized by any of the loaded drivers). Normally, a JDBC 4.0 driver should be autoloaded when you just drop it in runtime classpath. To exclude one and other, you can always manually load it as below:
System.out.println("Loading driver...");
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Driver loaded!");
} catch (ClassNotFoundException e) {
throw new IllegalStateException("Cannot find the driver in the classpath!", e);
}
Note that the newInstance() call is not needed here. It's just to fix the old and buggy org.gjt.mm.mysql.Driver. Explanation here. If this line throws ClassNotFoundException, then the JAR file containing the JDBC driver class is simply not been placed in the classpath.
Note that you don't need to load the driver everytime before connecting. Just only once during application startup is enough.
If you get a SQLException: Connection refused or Connection timed out or a MySQL specific CommunicationsException: Communications link failure, then it means that the DB isn't reachable at all. This can have one or more of the following causes:
IP address or hostname in JDBC URL is wrong.
Hostname in JDBC URL is not recognized by local DNS server.
Port number is missing or wrong in JDBC URL.
DB server is down.
DB server doesn't accept TCP/IP connections.
DB server has run out of connections.
Something in between Java and DB is blocking connections, e.g. a firewall or proxy.
To solve the one or the other, follow the following advices:
Verify and test them with ping.
Refresh DNS or use IP address in JDBC URL instead.
Verify it based on my.cnf of MySQL DB.
Start the DB.
Verify if mysqld is started without the --skip-networking option.
Restart the DB and fix your code accordingly that it closes connections in finally.
Disable firewall and/or configure firewall/proxy to allow/forward the port.
Note that closing the Connection is extremely important. If you don't close connections and keep getting a lot of them in a short time, then the database may run out of connections and your application may break. Always acquire the Connection in a try-with-resources statement. Or if you're not on Java 7 yet, explicitly close it in finally of a try-finally block. Closing in finally is just to ensure that it get closed as well in case of an exception. This also applies to Statement, PreparedStatement and ResultSet.
That was it as far the connectivity concerns. You can find here a more advanced tutorial how to load and store fullworthy Java model objects in a database with help of a basic DAO class.
Using a Singleton Pattern for the DB connection is a bad approach. See among other questions: Is it safe to use a static java.sql.Connection instance in a multithreaded system?. This is a #1 starters mistake.
DriverManager is a fairly old way of doing things. The better way is to get a DataSource, either by looking one up that your app server container already configured for you:
Context context = new InitialContext();
DataSource dataSource = (DataSource) context.lookup("java:comp/env/jdbc/myDB");
or instantiating and configuring one from your database driver directly:
MysqlDataSource dataSource = new MysqlDataSource();
dataSource.setUser("scott");
dataSource.setPassword("tiger");
dataSource.setServerName("myDBHost.example.org");
and then obtain connections from it, same as above:
Connection conn = dataSource.getConnection();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT ID FROM USERS");
...
rs.close();
stmt.close();
conn.close();
Initialize database constants
Create constant properties database username, password, URL and drivers, polling limit etc.
// init database constants
// com.mysql.jdbc.Driver
private static final String DATABASE_DRIVER = "com.mysql.cj.jdbc.Driver";
private static final String DATABASE_URL = "jdbc:mysql://localhost:3306/database_name";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
private static final String MAX_POOL = "250"; // set your own limit
Initialize Connection and Properties
Once the connection is established, it is better to store for reuse purpose.
// init connection object
private Connection connection;
// init properties object
private Properties properties;
Create Properties
The properties object hold the connection information, check if it is already set.
// create properties
private Properties getProperties() {
if (properties == null) {
properties = new Properties();
properties.setProperty("user", USERNAME);
properties.setProperty("password", PASSWORD);
properties.setProperty("MaxPooledStatements", MAX_POOL);
}
return properties;
}
Connect the Database
Now connect to database using the constants and properties initialized.
// connect database
public Connection connect() {
if (connection == null) {
try {
Class.forName(DATABASE_DRIVER);
connection = DriverManager.getConnection(DATABASE_URL, getProperties());
} catch (ClassNotFoundException | SQLException e) {
// Java 7+
e.printStackTrace();
}
}
return connection;
}
Disconnect the database
Once you are done with database operations, just close the connection.
// disconnect database
public void disconnect() {
if (connection != null) {
try {
connection.close();
connection = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
Everything together
Use this class MysqlConnect directly after changing database_name, username and password etc.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
public class MysqlConnect {
// init database constants
private static final String DATABASE_DRIVER = "com.mysql.cj.jdbc.Driver";
private static final String DATABASE_URL = "jdbc:mysql://localhost:3306/database_name";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
private static final String MAX_POOL = "250";
// init connection object
private Connection connection;
// init properties object
private Properties properties;
// create properties
private Properties getProperties() {
if (properties == null) {
properties = new Properties();
properties.setProperty("user", USERNAME);
properties.setProperty("password", PASSWORD);
properties.setProperty("MaxPooledStatements", MAX_POOL);
}
return properties;
}
// connect database
public Connection connect() {
if (connection == null) {
try {
Class.forName(DATABASE_DRIVER);
connection = DriverManager.getConnection(DATABASE_URL, getProperties());
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
}
}
return connection;
}
// disconnect database
public void disconnect() {
if (connection != null) {
try {
connection.close();
connection = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
How to Use?
Initialize the database class.
// !_ note _! this is just init
// it will not create a connection
MysqlConnect mysqlConnect = new MysqlConnect();
Somewhere else in your code ...
String sql = "SELECT * FROM `stackoverflow`";
try {
PreparedStatement statement = mysqlConnect.connect().prepareStatement(sql);
... go on ...
... go on ...
... DONE ....
} catch (SQLException e) {
e.printStackTrace();
} finally {
mysqlConnect.disconnect();
}
This is all :) If anything to improve edit it! Hope this is helpful.
String url = "jdbc:mysql://127.0.0.1:3306/yourdatabase";
String user = "username";
String password = "password";
// Load the Connector/J driver
Class.forName("com.mysql.jdbc.Driver").newInstance();
// Establish connection to MySQL
Connection conn = DriverManager.getConnection(url, user, password);
Here's the very minimum you need to get data out of a MySQL database:
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection conn = DriverManager.getConnection
("jdbc:mysql://localhost:3306/foo", "root", "password");
Statement stmt = conn.createStatement();
stmt.execute("SELECT * FROM `FOO.BAR`");
stmt.close();
conn.close();
Add exception handling, configuration etc. to taste.
you need to have mysql connector jar in your classpath.
in Java JDBC API makes everything with databases. using JDBC we can write Java applications to
1. Send queries or update SQL to DB(any relational Database)
2. Retrieve and process the results from DB
with below three steps we can able to retrieve data from any Database
Connection con = DriverManager.getConnection(
"jdbc:myDriver:DatabaseName",
dBuserName,
dBuserPassword);
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM Table");
while (rs.next()) {
int x = rs.getInt("a");
String s = rs.getString("b");
float f = rs.getFloat("c");
}
You can see all steps to connect MySQL database from Java application here. For other database, you just need to change the driver in first step only. Please make sure that you provide right path to database and correct username and password.
Visit http://apekshit.com/t/51/Steps-to-connect-Database-using-JAVA
MySQL JDBC Connection with useSSL.
private String db_server = BaseMethods.getSystemData("db_server");
private String db_user = BaseMethods.getSystemData("db_user");
private String db_password = BaseMethods.getSystemData("db_password");
private String connectToDb() throws Exception {
String jdbcDriver = "com.mysql.jdbc.Driver";
String dbUrl = "jdbc:mysql://" + db_server +
"?verifyServerCertificate=false" +
"&useSSL=true" +
"&requireSSL=true";
System.setProperty(jdbcDriver, "");
Class.forName(jdbcDriver).newInstance();
Connection conn = DriverManager.getConnection(dbUrl, db_user, db_password);
Statement statement = conn.createStatement();
String query = "SELECT EXTERNAL_ID FROM offer_letter where ID =" + "\"" + letterID + "\"";
ResultSet resultSet = statement.executeQuery(query);
resultSet.next();
return resultSet.getString(1);
}
Short and Sweet code.
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Driver Loaded");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/testDB","root","");
//Database Name - testDB, Username - "root", Password - ""
System.out.println("Connected...");
} catch(Exception e) {
e.printStackTrace();
}
For SQL server 2012
try {
String url = "jdbc:sqlserver://KHILAN:1433;databaseName=testDB;user=Khilan;password=Tuxedo123";
//KHILAN is Host and 1433 is port number
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
System.out.println("Driver Loaded");
conn = DriverManager.getConnection(url);
System.out.println("Connected...");
} catch(Exception e) {
e.printStackTrace();
}
Connection I was using some time ago, it was looking like the easiest way, but also there were recommendation to make there if statement- exactly
Connection con = DriverManager.getConnection(
"jdbc:myDriver:DatabaseName",
dBuserName,
dBuserPassword);
if (con != null){
//..handle your code there
}
Or something like in that way :)
Probably there's some case, while getConnection can return null :)
HOW
To set up the Driver to run a quick sample
1. Go to https://dev.mysql.com/downloads/connector/j/, get the latest version of Connector/J
2. Remember to set the classpath to include the path of the connector jar file.
If we don't set it correctly, below errors can occur:
No suitable driver found for jdbc:mysql://127.0.0.1:3306/msystem_development
java.lang.ClassNotFoundException: com.mysql.jdbc:Driver
To set up the CLASSPATH
Method 1: set the CLASSPATH variable.
export CLASSPATH=".:mysql-connector-java-VERSION.jar"
java MyClassFile
In the above command, I have set the CLASSPATH to the current folder and mysql-connector-java-VERSION.jar file. So when the java MyClassFile command executed, java application launcher will try to load all the Java class in CLASSPATH.
And it found the Drive class => BOOM errors was gone.
Method 2:
java -cp .:mysql-connector-java-VERSION.jar MyClassFile
Note: Class.forName("com.mysql.jdbc.Driver"); This is deprecated at this moment 2019 Apr.
Hope this can help someone!
MySql JDBC Connection:
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/DatabaseName","Username","Password");
Statement stmt=con.createStatement();
stmt = con.createStatement();
ResultSet rs=stmt.executeQuery("Select * from Table");
Short Code
public class DB {
public static Connection c;
public static Connection getConnection() throws Exception {
if (c == null) {
Class.forName("com.mysql.jdbc.Driver");
c =DriverManager.getConnection("jdbc:mysql://localhost:3306/DATABASE", "USERNAME", "Password");
}
return c;
}
// Send data TO Database
public static void setData(String sql) throws Exception {
DB.getConnection().createStatement().executeUpdate(sql);
}
// Get Data From Database
public static ResultSet getData(String sql) throws Exception {
ResultSet rs = DB.getConnection().createStatement().executeQuery(sql);
return rs;
}
}
Download JDBC Driver
Download link (Select platform independent): https://dev.mysql.com/downloads/connector/j/
Move JDBC Driver to C Drive
Unzip the files and move to C:\ drive. Your driver path should be like C:\mysql-connector-java-8.0.19\mysql-connector-java-8.0.19
Run Your Java
java -cp "C:\mysql-connector-java-8.0.19\mysql-connector-java-8.0.19\mysql-connector-java-8.0.19.jar" testMySQL.java
testMySQL.java
import java.sql.*;
import java.io.*;
public class testMySQL {
public static void main(String[] args) {
// TODO Auto-generated method stub
try
{
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con=DriverManager.getConnection(
"jdbc:mysql://localhost:3306/db?useSSL=false&useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC","root","");
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("show databases;");
System.out.println("Connected");
}
catch(Exception e)
{
System.out.println(e);
}
}
}
Trying to connect to a database on the system automatically.
The database is in the default Derby folder, created via NetBeans.
What I want to do is start the server and connect to the already existing database.
public void startServer() throws Exception {
NetworkServerControl server = new NetworkServerControl();
server.start(prntWrt);
}
#Override
public void start(Stage primaryStage) throws IOException, Exception {
startServer();
Pane root = (Pane) FXMLLoader.load(InteractiveFictionGame2.class.getResource("MainMenu.fxml"));
Scene scene = new Scene(root);
primaryStage.setTitle("MainMenu");
primaryStage.setScene(scene);
primaryStage.setFullScreen(true);
primaryStage.show();
}
It seems that the server does start but for some reason I can't connect to the database as it thinks it is non existant.
String host = "jdbc:derby://localhost:1527/InteractiveGameDatabase";
String unm = "Kylar";
String pswrd = "aswzxc";
public void loadImg() throws IOException {
try {
String SQL = "select vista from location where ycoordinate = ? and xcoordinate = ?";
Stage stage = new Stage();
con = DriverManager.getConnection(host, unm, pswrd);
stmnt = con.prepareStatement(SQL);
stmnt.setInt(1, ycoord);
stmnt.setInt(2, xcoord);
rs = stmnt.executeQuery();
rs.next();
fis = rs.getBinaryStream(1);
BufferedImage imgt = null;
try {
imgt = javax.imageio.ImageIO.read(fis);
} catch (IOException ex) {
System.out.println("Image failed to load.");
}
Image newImg = SwingFXUtils.toFXImage(imgt, null);
fadeInImage();
img_1.setFitHeight(880);
img_1.setImage(newImg);
img_1.setPreserveRatio(true);
img_1.setCache(true);
CountDownLatch doneLatch = new CountDownLatch(1);
animateUsingTimeline();
stck1.getChildren().addAll();
Scene scene = new Scene(stck1);
stage.setTitle("Interactive Fiction Game");
stage.setScene(scene);
stage.setFullScreen(true);
stage.show();
rs.close();
stmnt.close();
con.close();
} catch (SQLException e) {
System.out.println(e.getMessage());
}
}
I get an error "The connection was refused because the database InteractiveGameDatabase was not found.". If I start the server through the NetBeans IDE and then run the application everything is perfect. Any help will be appreciated.
Since you specified:
String host = "jdbc:derby://localhost:1527/InteractiveGameDatabase";
as your connection URL, the Derby Network Server is looking for the database using the relative database name "InteractiveGameDatabase". Since that is a relative name, not an absolute name, the Derby Network Server will look for the database in its home directory, which is typically whatever was the current directory when you started the Derby Network Server.
So probably what's going here is that when you run the Derby Network Server in NetBeans, it runs with a certain directory as its home directory, according to how NetBeans starts it up.
But when you run the Derby Network Server yourself, by hand, it runs in a different directory as its home directory, because you didn't precisely start it up in the same directory where NetBeans starts it up, and hence it can't find the database InteractiveGameDatabase in this new directory.
You could:
Always use the NetBeans-started Derby Network Server
Start your own Network Server, but arrange to do so in the same directory where NetBeans starts the Derby Network Server
Start your own Network Server, but change your connection URL to specify the full absolute path to the location where the NetBeans-started Derby Network Server was run, so that your Network Server can access that directory when you go to open the database.
There are many other possibilities, but hopefully these are enough to give you an idea about what's going on.
I have several WebMethods involving sql, when I call a method it sends a soapException involving the com.mysql.jdbc.driver
This is my connection method (it is not a web method but it is on the web service class along with the rest of the web methods)
public Connection connect() throws Exception
{
if (con == null)
{
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ProyectGameSmart","root","root");
}
return con;
}
This is one of the web methods that need to get a connection instance
public int insert_publisher(String pub, String phone, String addr) throws Exception
{
int ResultValue = 0;
connect();
query="INSERT INTO ProyectGameSmart.Publisher(Publisher,Phone,Address)VALUES('"+pub+"','"+phone+"','"+addr+"');";
pstmt = con.prepareStatement(query);
ResultValue = pstmt.executeUpdate();
return ResultValue;
}
Can anyone help me on how to implement a web service involving sql connection. I have only been able to find web services with simple math methods. I'm using Eclipse and Tomcat 7.
Thank you in advance
If your code is working locally, I mean without running as a web service. Then You have to put the correct version of the mysql JDBC driver in to your classpath of the web services server. Here Tomcat lib folder. That will solve th problem.
I'm building a desktop app that needs to communicate with a MS Access database. Now, unless I want to register the DSN for the database on every computer that's going to use the desktop app, I need a way to connect to the database in a DSN-less fashion.
I've searched alot and found some useful links on how to create connection strings and based on that I tried modifying my program based on that but without success.
The code below fails. If i switch the string in the getConnection to "jdbc:odbc:sampleDB" it works, but that's using DSN and not what I want to achieve.
How do I write and use a connection string in java to make a DSN-less connection to a MS Access database?
private Connection setupConnection() throws ClassNotFoundException,
SQLException {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con = DriverManager.getConnection("Driver={Microsoft Access Driver (*.mdb)} &_ Dbq=c:\\as\\sampleDB.mdb");
return con;
}
Addition: I'd also like to point out that if anyone has an idea of a way to achieve what I asked for WITH a DSN-connection I'll gladly listen to it!
JDBC connection string shouls start with jdbc: like:
jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=c:\\Nwind.mdb
so try with:
Connection con = DriverManager.getConnection("jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};Dbq=c:\\as\\sampleDB.mdb");
If you configure DSN then you can connect to it using simplier connect string: jdbc:odbc:[alias], example:
jdbc:odbc:northwind
I also had this problem and tried many of the suggestions here and on various forums. Finally, I discovered a snippet from one place which led to success connecting and also explains why many of these posts do not work. See http://www.coderanch.com/t/295299/JDBC/databases/jdbc-odbc-DSN-connection-MS
The issue is that there must be a semicolon after the colon at the end of odbc as in jdbc:odbc:;Driver= . This made sense after reading the Oracle documentation on the JdbcOdbc bridge which states that the syntax is jdbc:odbc:dsn; attributes....... Since we are not supplying a DSN, then we need to end with ; before adding attributes.
I am showing below the tests I ran with different connection strings on a Windows 7 Ultimate 32bit machine:
driver= (Driver)Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
//jdbc:odbc:Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ= does lookup to ODBC.ini to find matching driver
try {
connstr= "jdbc:odbc:;Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=" + fileURI; //64 bit ?? (*.mdb,*.accdb)
conn= DriverManager.getConnection(connstr, "", "");
stmt= conn.createStatement();
}
catch (Exception e){}
try {
connstr= "jdbc:odbc:;Driver={Microsoft Access Driver (*.mdb)};DBQ=" + fileURI; //64 bit ?? (*.mdb,*.accdb)
conn1= DriverManager.getConnection(connstr, "", "");
stmt1= conn1.createStatement();
dbmeta1=conn1.getMetaData();
}
catch (Exception e){}
try {
connstr= "jdbc:odbc:MS Access Database;DBQ=" + fileURI; //64 bit ?? (*.mdb,*.accdb)
conn2= DriverManager.getConnection(connstr, "", "");
stmt2= conn2.createStatement();
dbmeta2=conn2.getMetaData();
}
catch (Exception e){}
try {
connstr= "jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=" + fileURI; //64 bit ?? (*.mdb,*.accdb)
conn3= DriverManager.getConnection(connstr, "", "");
stmt3= conn3.createStatement();
dbmeta3=conn3.getMetaData();
}
catch (Exception e){}
stmt1 and stmt3 are null since the connections are null. stmt and stmt2 work. stmt2 uses a connection string I found in the documentation for IBM Tivoli. It works because "MS Access Database" is a valid title in the ODBC registry as a User DSN on my computer.