When I run my code, I just keep getting the error:
"ResultSet not open. Verify that autocommit is OFF."
How can I fix it?
I can't get it to work. I'm sure it has to do with con.setAutoCommint(false); or executeQuery.
package database_console;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import static jdk.nashorn.internal.objects.NativeString.split;
import java.sql.*;
import java.sql.ResultSet;
import java.util.Random;
public class Database_console {
public static void main(String[] args) {
String url = "jdbc:derby://localhost:1527/English Words";
try {
String host = "jdbc:derby://localhost:1527/English Words";
String uName = "User";
String uPass= "password";
Connection con = DriverManager.getConnection(host, uName, uPass);
con.setAutoCommit(false);
Statement stmt = con.createStatement();
String SQL1 = "SELECT * FROM ENGLISH_1";
String SQL2 = "SELECT * FROM ENGLISH_2";
String SQL3 = "SELECT * FROM ENGLISH_3";
String SQL4 = "SELECT * FROM ENGLISH_4";
String SQL5 = "SELECT * FROM ENGLISH_5";
ResultSet rs1 = stmt.executeQuery( SQL1);
ResultSet rs2 = stmt.executeQuery( SQL2);
ResultSet rs3 = stmt.executeQuery( SQL3);
ResultSet rs4 = stmt.executeQuery( SQL4);
ResultSet rs5 = stmt.executeQuery( SQL5);
while(rs1.next()) {
String 1 = rs1.getString("1");
String 2 = rs2.getString("2");
String 3 = rs3.getString("3");
String 4 = rs4.getString("4");
String 5 = rs5.getString("5");
con.commit();
System.out.println( 1 + " " + 2 + " " + 3 " " + 4 " " 5 + " ");
}
}
catch (SQLException err) {
System.out.println(err.getMessage());
}
}
}
Two things: First, COMMIT closes out transactions that start with BEGIN TRANSACTION. You don't have any of those.
Second, When you're using JDBC to execute SELECT statements, you need to execute each SQL statement, then retrieve and close its result set, before starting the next one. The code you showed tries to create a bunch of ResultSet objects and then read them one by one. You Can't Do That.™
Important: Don't forget to close() each ResultSet when you're done with it. ResultSets can be scarce resources on your database servers.
For example, try this.
String SQL1 = "SELECT col1, col2, col3 FROM ENGLISH_1";
String SQL2 = "SELECT col1, col2, col3 FROM ENGLISH_2";
Statement stmt = con.createStatement( );
ResultSet rs1 = stmt.executeQuery( SQL1 );
while(rs1.next()) {
String s1 = rs1.getString(1);
String s2 = rs1.getString(2);
String s3 = rs1.getString(3);
System.out.println( s1 + " " + s2 + " " + s3);
}
rs1.close();
ResultSet rs2 = stmt.executeQuery( SQL2 );
while(rs2.next()) {
String t1 = rs2.getString(1);
String t2 = rs2.getString(2);
String t3 = rs2.getString(3);
System.out.println( t1 + " " + t2 + " " + t3);
}
rs2.close();
Related
I have established a connection with mySql and Java and currently I can run a query from my database. I can run queries such as "Select * from Customer".
The problem appears, when i try to scan a value from the user and try to run it in my db.
select E.rent_id, name, telephone, Pa.date_get, Pr.date_return
from Rent as E, Customer as P, Get as Pa, return as Pr, Makes as Pg
where E.rent_id = Pg.rent_id
and Pg.cust_id = P.cust_id
and E.rent_id = Pa.rent_id
and E.rent_id = Pr.rent_id
and Month (Pa.date_get) = #input
and Year (Pa.date_get) = #input;
This is a query, which selects an id, a name, telephone, and dates of get and return of a vehicle (this is a db for a car rental company).
Unfortunately, when I connect to my db via Java, using the connector, I can't run this query.
Do you have any idea what to do?
Here follows the code in java that makes the connection and the use of the query, stated above.
package database;
import java.util.Scanner;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class Connect {
public void databaseConnect(String connect_string, String username, String password) {
try {
Scanner scanner = new Scanner (System.in);
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(connect_string, username, password);
System.out.println("Connection Succesful");
Statement statement = conn.createStatement();
System.out.println("Insert month: ");
int mina = scanner.nextInt();
System.out.println("Insert year: ");
int xrono = scanner.nextInt();
String query = "select E.rent_id, name, telephone, Pa.date_get, Pr.date_return\r\n" +
"from Rent as E, Customers P, Get as Pa, return as Pr, makes as Pg\r\n" +
"where E.rent_id = Pg.rent_id \r\n" +
"and Pg.cust_id = P.cust_id \r\n" +
"and E.rent_id = Pa.rent_id \r\n" +
"and E.rent_id = Pr.rent_id \r\n" +
"and Month (Pa.date_get) = #mina \r\n" +
"and Year (Pa.date_get) = #xrono;";
ResultSet rs = statement.executeQuery(query);
while (rs.next()) {
System.out.println(rs.getString(1));
System.out.println(rs.getString(2));
System.out.println(rs.getString(3));
System.out.println(rs.getString(4));
System.out.println(rs.getString(5));
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Connect connectToServer = new Connect();
connectToServer.databaseConnect("jdbc:mysql://localhost/acr", "/*username*/", "/*password*/");
}
}
Can you see a mistake?
Thank you so much in advance!
Have sqlite table named good_in with columns in_id, good_code, in_group, in_quantity, in_VATPaid
Here is my table example
and have method to insert records into it
public static void inputGoods(GoodsInput goodsinput){
String goodCode = goodsinput.getInGood().getGood_code();
int goodBatch = goodsinput.getInGroup();
int goodQuantity = goodsinput.getInQuantity();
double goodVATPaid = goodsinput.getInVatPaid();
String sqlInsert = "INSERT INTO good_in (good_code, in_group, in_quantity, in_VATPaid)"
+ " VALUES ('" + goodCode + "', " + "'" + goodBatch + "', " + "'" + goodQuantity
+ "', " + "'" +goodVATPaid + "');";
System.out.print(sqlInsert);
Connection conn = ConnectionFactory.ConnectDB();
try{
Statement statement = conn.createStatement();
statement.executeUpdate(sqlInsert);
}
catch(SQLException e){
}
}
Connection class
public static Connection ConnectDB(){
try{
Class.forName("org.sqlite.JDBC");
Connection con = DriverManager.getConnection("jdbc:sqlite:kahuyq.db");
return con;
} catch (HeadlessException | ClassNotFoundException | SQLException ex){ JOptionPane.showMessageDialog(null, ex); }
return null;
}
When I copy the printed query to sqlite manager it adds the row, but from java it ends program with no error but does not add row to my table.
What is wrong?
Have also other method that checks weather the good_code exists in table good which have only 2 columns id and good_code and if does not exist adds it. this method is accessed from GoodsInput constructor. When I delete the method from constructor the other method works fine.
Here is that method
public static void insertGoods(Good g){
String sqlSelect = "Select * from good where good_code = '"
+ g.getGood_code() + "'" ;
String sqlInsert = "INSERT INTO good (good_code)"
+ "VALUES ('" + g.getGood_code() +"')";
Connection conn = ConnectionFactory.ConnectDB();
try{
Statement statement = conn.createStatement();
ResultSet rs = statement.executeQuery(sqlSelect);
while(!rs.next()){
statement.executeUpdate(sqlInsert);
break;
}
}
catch(SQLException e){
}
}
Try to add
conn.commit();
after the execution of your statement.
I have the following function and I am trying to compare the number of students enrolled in a class with the class max. If the number enrolled is greater than the class max, I want to return a message that says, "The Class if Full".
public static void classFullCheck() {
try {
String currentNumberInClassAsString = ("SELECT class_id, COUNT(*) FROM ClassSelector.student_x_class WHERE class_id = " + selectedClass);
rs = myStmt.executeQuery(currentNumberInClassAsString);
int currentNumberInClassAsInt = 0;
if(rs.next()){
currentNumberInClassAsInt = rs.getInt(1);
}
String classSizeAsString = ("SELECT class_size FROM ClassSelector.classes WHERE class_id = " + selectedClass);
rs = myStmt.executeQuery(classSizeAsString);
int classSizeAsInt = 0;
if(rs.next()){
classSizeAsInt = rs.getInt("class_size");
}
if (currentNumberInClassAsInt > classSizeAsInt){
System.out.println("Sorry, this class is Full!");
}
} catch (java.sql.SQLException SQL) {
SQL.printStackTrace();
}
}
I am inserting the classFullcheck() function into the addClass() function like this:
public static void addClass() {
try {
rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes");
while (rs.next()) {
String availableClasses = rs.getString("class_id") + "\t" + rs.getString("class_name") + "\t" + rs.getString("description");
System.out.println(availableClasses);
}
System.out.println("Enter Class ID from Classes Listed Above to Join: ");
selectedClass = sc.nextLine();
rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass);
while (rs.next()) {
classFullCheck();
String innerJoin = (userEnterIdAsName + " has been added to " + rs.getString("class_name") + " " + rs.getString("class_id"));
System.out.println(innerJoin);
String student_x_classJoin = "INSERT INTO student_x_class" + "(student_id, student_name, class_id, class_name)" + "VALUES (?, ?, ?, ?)";
PreparedStatement pStmt = con.prepareStatement(student_x_classJoin);
pStmt.setString(1, user_entered_student_id);
pStmt.setString(2, userEnterIdAsName);
pStmt.setString(3, rs.getString("class_id"));
pStmt.setString(4, rs.getString("class_name"));
pStmt.executeUpdate();
System.out.println("Would you like to enroll " + userEnterIdAsName + " into another class? (Y/N)");
String addAdditionalClass = sc.nextLine();
if (addAdditionalClass.equalsIgnoreCase("Y")) {
addClass();
} else if (addAdditionalClass.equalsIgnoreCase("N")) {
return;
}
}
}
catch (java.sql.SQLException SQL) {
System.out.println("Wait, This Student is already enrolled in this class!");
}
}
I am currently just getting both messages printed out, even if a class is not full. Any suggestions would help a lot.
if (currentNumberInClassAsInt >= classSizeAsInt) {
String updateStatus = "Update ClassSelector.classes SET status = ? WHERE class_id = " + selectedClass;
PreparedStatement pStmt = con.prepareStatement(updateStatus);
pStmt.setString(1, "Closed");
pStmt.executeUpdate();
System.out.println("Sorry, this class is Full! Select a different Class:");
System.out.println("\nSign Up For a Class\n");
addClass();
}
I think you want this:
currentNumberInClassAsInt = rs.getInt(2);
instead of:
currentNumberInClassAsInt = rs.getInt(**1**);
I don't think the ResultSet is 0 based...
Also is rs a global variable because it looks like you are changing your ResultSet rs when you call classFullCheck(). You may not have what you think you do in the ResultSet...
rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass);
while (rs.next()) {
classFullCheck();//****************result set changed here******************
String innerJoin = (userEnterIdAsName + " has been added to " + rs.getString("class_name") + " " + rs.getString("class_id"));
You may think you have this: rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass); in your result set but you change rs in classFullCheck(). You may want to store the data in a different object that way when you run another query you can still access the data.
I have the following code :
try{
String select2 = "INSERT INTO employees VALUES (17, 'Adam', 'Kizzam', 'aa#zz.com', '123-456-7890', '12-DEC-00', '1234', '12345.23, 50', '12.25', 1222, 4769 ) ";
PreparedStatement preparedStatement2 = connection.prepareStatement(select2); // dbConnection. prepareStatement(selectSQL);
ResultSet rs2 = preparedStatement2.executeUpdate(select2);
while (rs.next()) {
String userid = rs.getString("EMPLOYEE_ID");
String username = rs.getString("FIRST_NAME");
System.out.println ("the userid , username are " + userid + " " + username);
} }
This gives me the following error :
Error(54,77): incompatible types; required: java.sql.ResultSet;
found:
int DBConnection.java C:\JDeveloper\mywork\OracleDatabaseApp\OracleDatabaseApp\src\oracledatabaseapp OracleDatabaseApp.jpr
executeUpdate returns an int
int rows = preparedStatement2.executeUpdate(select2);
I am trying to develop a simple Java DVD library console app in Java. I have created a database table that contains a list of DVD's. I have managed to get the adding a new DVD to the database functionally working, but I am struggling to delete a row from the database. When I use a SQL statement to select a row (row 7) then run the line 'rs.delete' I get the following exception:-
Invalid cursor state - no current row.
Below is my database table:-
ID Film Name Genre Rating
-------------------------------
1 Robocop Sci-fi 18
2 Terminator Sci-fi 18
3 Alien Sci-fi 18
4 Big Fish Fantasy PG
5 The Pianist Drama 18
6 Total Recall Sci-fi 18
7 Carnage Comedy 18
Below is copy of my code. Please could somebody help?
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package dvdlibrary;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import javax.swing.JOptionPane;
import java.util.Scanner;
/**
*
* #author Andy
*/
public class DVDLibrary {
Connection con;
Statement stmt;
ResultSet rs;
String selection = "";
int id_num =0;
String film_name ="";
String genre ="";
String rating="";
public DVDLibrary()
{
DoConnect();
}
public void DoConnect() {
try
{
String host = "jdbc:derby://localhost:1527/DVDLibrary";
String username = "andyshort";
String password = "Pa55word";`enter code here`
con = DriverManager.getConnection(host, username, password);
stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String SQL = "SELECT * FROM ANDYSHORT.DVDS";
rs = stmt.executeQuery(SQL);
/*
System.out.println("ID Film Name Genre Rating");
System.out.println("-------------------------------");
while (rs.next())
{
int id_col = rs.getInt("ID");
String film_name_col = rs.getString("Film_Name");
String genre_col = rs.getString("Genre");
String rating_col = rs.getString("Rating");
String p = id_col + " " + film_name_col + " " + genre_col + " " + rating_col;
System.out.println(p);
//System.out.format("%32s%10d%16s", id_col , film_name_col, genre_col, rating_col);
}
*/
}
catch (SQLException err)
{
System.out.println(err.getMessage());
}
}
public void GetUserInput()
{
System.out.println();
System.out.println("What would you like to do? Choose one of the following options.");
System.out.println("1. Display DVD library list");
System.out.println("2. Add a new film to database.");
System.out.println("3. Delete a film from the database.");
System.out.println();
Scanner user_option_selection = new Scanner(System.in);
selection = user_option_selection.next();
if(selection.equalsIgnoreCase("1"))
{
DisplayDVDList();
}
else if(selection.equalsIgnoreCase("2"))
{
AddRecord();
}
else if(selection.equalsIgnoreCase("3"))
{
DeleteRecord();
}
else
{
System.out.println("Incorrect option entered. Please try again.");
}
}
public void DisplayDVDList()
{
try
{
String SQL = "SELECT * FROM ANDYSHORT.DVDS";
rs = stmt.executeQuery(SQL);
System.out.println("ID Film Name Genre Rating");
System.out.println("-------------------------------");
while (rs.next())
{
int id_col = rs.getInt("ID");
String film_name_col = rs.getString("Film_Name");
String genre_col = rs.getString("Genre");
String rating_col = rs.getString("Rating");
String p = id_col + " " + film_name_col + " " + genre_col + " " + rating_col;
System.out.println(p);
//System.out.format("%32s%10d%16s", id_col , film_name_col, genre_col, rating_col);
}
}
catch (SQLException err)
{
System.out.println(err.getMessage());
}
GetUserInput();
}
public void AddRecord()
{
Scanner new_film_details = new Scanner(System.in);
System.out.println("Please enter film name: ");
film_name = new_film_details.next();
System.out.println("Please enter film genre: ");
genre = new_film_details.next();
System.out.println("Please enter film rating: ");
rating = new_film_details.next();
try
{
rs.last();
id_num = rs.getRow();
id_num = id_num + 1;
rs.moveToInsertRow();
rs.updateInt("ID", id_num);
rs.updateString("FILM_NAME", film_name);
rs.updateString("GENRE", genre);
rs.updateString("RATING", rating);
rs.insertRow();
//stmt.close( );
//rs.close( );
}
catch(SQLException err)
{
System.out.println(err.getMessage());
}
GetUserInput();
}
public void DeleteRecord()
{
String id = "";
Scanner id_of_film_to_delete= new Scanner(System.in);
System.out.println("Enter ID of film you want to delete.");
id = id_of_film_to_delete.next();
int idInt = Integer.parseInt(id);
try
{
stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String sql = "SELECT * FROM ANDYSHORT.DVDS WHERE ID =" + idInt;
rs = stmt.executeQuery(sql);
rs.deleteRow();
}
catch(SQLException err)
{
System.out.println(err.getMessage());
}
GetUserInput();
}
}
use directly this query
"DELETE FROM ANDYSHORT.DVDS WHERE ID =" + idInt;
String sql = "DELETE FROM ANDYSHORT.DVDS WHERE ID=?";
PreparedStatement statement = conn.prepareStatement(sql);
statement.setString(1, "+ idInt+");
int rowsDeleted = statement.executeUpdate();
if (rowsDeleted > 0) {
System.out.println(" delete successfully!");
}
Use prepared statements to avoid SQL injection:
PreparedStatement statement;
statement = con.prepareStatement("DELETE FROM andyshort.dvds WHERE id = ?");
statement.setInt(1, idToDelete);
statement.executeUpdate();
You can directly use delete query if you have the Id before hand.
String sql = "DELETE FROM ANDYSHORT.DVDS WHERE ID =" + idInt;
stmt.executeUpdate(sql);
But, it's better to use prepared statements instead of statements in order to avoid sql injection attacks.
String query= "DELETE FROM ANDYSHORT.DVDS WHERE ID = ? ";
PreparedStatement preparedStatement = con.prepareStatement(query);
preparedStatement.setInt(1,idInt);
preparedStatement.executeUpdate();
You need to move the cursor to the first row before deleting the row, if you want to use deleteRow() method.
rs.first();
rs.deleteRow();