i am new in database want to run first database program with Access but getting SQLException message "DB linking failed!"
i wrote following code with Java 8,and i have configured ucanaccess's libraries.
Java build path
<i>
import java.sql.*;
public class Db {
public static void main(String[] args)throws SQLException
{
Connection con =null;
try{
Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
String dataSource = "jdbc:ucanaccess://D:/Database.accdb";
con=DriverManager.getConnection(dataSource,"","");
Statement st = con.createStatement();
st.executeUpdate("INSERT INTO Table1 (ID, Name) VALUES ('4','ann')");
st.execute("SELECT * FROM Table1");
ResultSet rs = st.getResultSet();
while(rs.next())
{
System.out.println(rs.getString("ID")+rs.getString("Name"));
}
st.close();
con.close();
}
catch(SQLException e)
{
System.out.println("DB linking failed!");
} catch (ClassNotFoundException e) {
System.out.println("Driver loading failed!");
}
}
}
i have added "e.printStackTrace()" in the catch block as following
catch(SQLException e)
{
e.printStackTrace();
} catch (ClassNotFoundException e) {
System.out.println("Driver loading failed!");
}
and got following error messages
error messages
Related
I try to connect to db2 from java, here is my code:
public class Db2Connection {
public static void main(String[] args) {
String jdbcClassName="com.ibm.db2.jcc.DB2Driver";
String url="jdbc:db2://localhost:50001/TEST";
String user="user1";
String password="pass";
System.out.println("before try-catch");
Connection connection = null;
try {
System.out.println("try");
//Load class into memory
Class.forName(jdbcClassName);
//Establish connection
System.out.println("before conn");
connection = DriverManager.getConnection(url, user, password);
System.out.println("after conn");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally{
if(connection!=null){
System.out.println("Connected successfully.");
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
To be clear, I add db2jcc.jar to my project and run code with valid url. Program cannot jump over line:
connection = DriverManager.getConnection(url, user, password);
I receive no errors or exception, application just not execute. I have no idea how deal with it, can anyone help me?
Try, after removing colon like :
String url="jdbc:db2//localhost:50001/TEST";
I've got a mysql question within java. I've got a mysql database with different tables. I currently got a database called 'litebans' and a table called 'litebans_mutes'.
Within that table there is a row called reason and under that reason (let's say what's within reason) there's a string called 'This is a test' and 'sorry'; how would I get the string 'This is a test' and 'sorry' associated with the same 'uuid' row in java? Here is a picture explaining more:
Here is an image explaining the sql format
Additionally, i've currently initialized all variables and such in java, i currently have this code:
http://hastebin.com/odumaqazok.java (Main class; using it for a minecraft plugin)
The below code is the MySQL class; api used to connect and execute stuff.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import net.octopusmc.punish.Core;
public class MySQL {
public static Connection openConnection() {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e1) {
System.err.println(e1);
e1.printStackTrace();
}
try {
Connection conn = DriverManager.getConnection("jdbc:mysql://" + Core.host + ":" + Core.port + "/" + Core.database, Core.user, Core.pass);
System.out.println("Currently connected to the database.");
return conn;
} catch (SQLException e) {
System.out.println("An error has occured while connecting to the database");
System.err.println(e);
e.printStackTrace();
}
return null;
}
public static void Update(String qry) {
try {
Statement stmt = Core.SQLConn.createStatement();
stmt.executeUpdate(qry);
stmt.close();
} catch (Exception ex) {
openConnection();
System.err.println(ex);
}
}
public static Connection getConnection() {
return Core.SQLConn;
}
public static ResultSet Query(String qry) {
ResultSet rs = null;
try {
Statement stmt = Core.SQLConn.createStatement();
rs = stmt.executeQuery(qry);
} catch (Exception ex) {
openConnection();
System.err.println(ex);
}
return rs;
}
}
An example using that api above is shown below:
try {
ResultSet rs = MySQL.Query("QUERY GOES HERE");
while (rs.next()) {
//do stuff
}
} catch (Exception err) {
System.err.println(err);
err.printStackTrace();
}
tl;dr: I want to get the two fields called 'reason' with the give 'uuid' string field.
First , make sure that your using the jdbc mysql driver to connect to the database
Defile a class where you could write the required connection and create statement code.
For example
class ConnectorAndSQLStatement {
ResultSet rs = null;
public Statement st = null;
public Connection conn = null;
public connect() {
try {
final String driver = "com.mysql.jdbc.Driver";
final String db_url = "jdbc:mysql://localhost:3306/your_db_name";
Class.forName(driver);//Loading jdbc Driver
conn = DriverManager.getConnection(db_url, "username", "password");
st = conn.createStatement();
rs = st.executeQuery("Select what_you_want from your_table_name");
while (rs.next()) {
String whatever = rs.getInt("whatever ");
System.out.print(whatever);
}
} catch (SQLException se) {
se.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
Just call this function and the magic :D
Hope it is helpful
Following is my Java code. In linux, it is working fine but in Windows I'm unable to insert data into the database on local disk. In NetBeans get it all right but .jar file not. JDBC driver see be good.
Connecting to database:
public static Connection connectToDb() {
try {
Connection connection = null;
DriverManager.registerDriver(new org.sqlite.JDBC());
//LINUX PATH
if (OSDetector.isLinux()) {
connection = DriverManager.getConnection("jdbc:sqlite:/home/" + userNameLinux + "/PDFMalwareDataAnalyser/DatabaseSQLite/database.db", NAME, PASSWORD);
//WINDOWS PATH
} else {
connection = DriverManager.getConnection("jdbc:sqlite:C:\\PDFMalwareDataAnalyser\\DatabaseSQLite\\database.db", NAME, PASSWORD);
}
connection.setAutoCommit(true);
if (connection != null) {
System.out.println("Otvorená.");
}
return connection;
} catch (SQLException e) {
System.err.println(e.getClass().getName() + e.getMessage());
// System.exit(0);
}
return null;
}
Insertion:
public void insertDataToDatabase(int idReport) throws SQLException {
connection = new SQLiteJDBC().connectToDb();
PreparedStatement insertCommunication = connection.prepareStatement("insert into table_communication values(?,?);");
insertCommunication.setString(2, communicationsFinal.toString());
try {
insertCommunication.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
}
insertCommunication.close();
connection.close();
System.out.println("1. --- Insert do tabuľky TABLE_COMMUNICATION OK ---");
}
Try this:
connection = DriverManager.getConnection("jdbc:sqlite:C:/PDFMalwareDataAnalyser/DatabaseSQLite/database.db")
I am going to enhance the performance of my program. For this purpose I am going to implement some parts of my program to be done in memory instead of database. I dont know which one is better in this regards, in-memory database or normal java data structure.For in-memory database I considered Tentimes from oracle and H2. So another question would be which solution is better for around 100 million records of data on single machine for single user? Also another question would be is the old way of database connection works fine in this way? Here is the connection that I used for oracle, What is the appropriate Driver for this purpose.
public static Connection getConnection(){
//If instance has not been created yet, create it
if(DatabaseManager.connection == null){
initConnection();
}
return DatabaseManager.connection;
}
//Gets JDBC connection instance
private static void initConnection(){
try{
Class.forName("oracle.jdbc.driver.OracleDriver");
String connectionUrl = "jdbc:oracle:thin:#localhost:1521:" + dbName;
DatabaseManager.connection =
DriverManager.getConnection(connectionUrl,"****","****");
}
catch (ClassNotFoundException e){
System.out.println("Oracle driver is not loaded!");
System.exit(0);
}
catch (SQLException e){
System.out.println(e.getMessage());
System.exit(0);
}
catch (Exception e){
}
}
public static ResultSet executeQuery(String SQL) throws SQLException
{
CachedRowSetImpl crs = new CachedRowSetImpl();
ResultSet rset = null ;
Statement st = null;
try {
st = DatabaseManager.getConnection().createStatement();
rset = st.executeQuery(SQL);
crs.populate(rset);
}
catch (SQLException e) {
System.out.println(e.getMessage());
System.exit(0);
}finally{
rset.close();
st.close();
}
return crs;
}
public static void executeUpdate(String SQL)
{
try {
Statement st = DatabaseManager.getConnection().createStatement();
st.executeUpdate(SQL);
// st.close();
}
catch (SQLException e) {
System.out.println(e.getMessage());
System.exit(0);
}
}
Regards.
public class Txt {
public static void main(String[] args) throws Exception {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:txt");
Statement st=con.createStatement();
ResultSet rs=st.executeQuery("select eno,ename from emp");
System.out.println(rs.getInt(1)+" "+rs.getString(2));
}
}
You should close the connection on end of your code;
con.close();
Use this example:
public static void main(String[] args) throws Exception {
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:txt");
Statement st=con.createStatement();
ResultSet rs=st.executeQuery("select eno,ename from emp");
System.out.println(rs.getInt(1)+" "+rs.getString(2));
}
catch (SQLException e) {
e.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
}
finally {
// Close the connection
con.close();
}
}
Good Luck!