guys. I learn java from few weeks and now i tried to insert my data from simple bank account application into MySQL table (the id and the name from the main class, and the balance and previous transaction from the other class). I want to save the balance and transactions when use particular name and id. This is my code:
import java.sql.*;
import java.util.Scanner;
public class BankingApp {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter your name: ");
String name = sc.next();
System.out.print("Enter your ID: ");
String id = sc.next();
System.out.println();
BankAccount bankAcc = new BankAccount(name, id);
bankAcc.showMenu();
bankAcc.insert();
sc.close();
}
}
class BankAccount {
float balance;
float prevTransaction;
String customerName;
String customerID;
BankAccount(String name, String id) {
customerName = name;
customerID = id;
}
void deposit(float amount) {
if (amount != 0) {
balance += amount;
prevTransaction = amount;
}
}
void withdraw(float amount) {
if (amount != 0) {
balance -= amount;
prevTransaction = -amount;
}
}
void getPreviousTransaction() {
if (prevTransaction > 0) {
System.out.println("Deposited: " + prevTransaction);
}
else if (prevTransaction < 0) {
System.out.println("Withdrawn: " + Math.abs(prevTransaction));
}
else {
System.out.println("No transaction is occured!");
}
}
void showMenu() {
char option = '\0';
Scanner sc = new Scanner(System.in);
System.out.println("Welcome " + customerName);
System.out.println("Your ID is: " + customerID);
System.out.println();
System.out.println("A. Check Balance");
System.out.println("B. Deposit");
System.out.println("C. Withdraw");
System.out.println("D. Previous Transaction");
System.out.println("E. Exit");
do {
System.out.println("=========================");
System.out.println("Enter the option");
System.out.println("=========================");
option = sc.next().charAt(0);
Character.toUpperCase(option);
switch (option) {
case 'A':
System.out.println("============================");
System.out.println("Balance: " + balance);
System.out.println("============================");
System.out.println();
break;
case 'B':
System.out.println("============================");
System.out.println("Enter the amount to deposit");
System.out.println("============================");
float amount = sc.nextFloat();
deposit(amount);
System.out.println();
break;
case 'C':
System.out.println("============================");
System.out.println("Enter the amount to withdraw");
System.out.println("============================");
float amount2 = sc.nextFloat();
withdraw(amount2);
System.out.println();
break;
case 'D':
System.out.println("============================");
getPreviousTransaction();
System.out.println("============================");
System.out.println();
break;
case 'E':
System.out.println("============================");
break;
default:
System.out.println("Invalid Option! Please try again!");
break;
}
} while (option != 'E');
sc.close();
}
public void insert() {
String myUrl = "jdbc:mysql://localhost:3306/bankacc";
String db_id = "root";
String db_pass = "Ik32e23k";
Connection conn = null;
Statement stmt = null;
try {
conn = DriverManager.getConnection(myUrl, db_id, db_pass);
stmt = conn.createStatement();
String sql = "insert into users" +
"(id, name, balance, transactions)" +
"values (" + customerID + ", " + customerName + ", " + balance + ", " + prevTransaction +")";
stmt.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (stmt != null)
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (conn != null)
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
When i tried to call my insert() method into the main method, i got the following error:
java.sql.SQLSyntaxErrorException: Unknown column 'Koko' in 'field list' at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:121) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) at com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1334) at com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2084) at com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1245) at BankAccount.insert(BankingApp.java:151) at BankingApp.main(BankingApp.java:18)
Instead of inserting my name into the table, the exception told me that my name is unknown column. I have only guesses where the problem could be coming from, but I have no idea how to do it. Can somebody explain me where is my bad? Thanks in advance!
