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Truncate table 表名
直接刪除表中全部數(shù)據(jù),與delete不同的是,此方法無(wú)法使用where選擇,只能全部刪除。
truncate table users;
Java連接數(shù)據(jù)庫(kù):
package com.edu.gkh;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;
public class Homework {
static Statement sc=null;
static Scanner sca=new Scanner(System.in);
static String username;
public static void main(String[] args) throws Exception {
getStatement();
String name2="";
String pwd2="";
for(;;){
System.out.println("請(qǐng)輸入注冊(cè)賬號(hào)");
String name=sca.next();
System.out.println("請(qǐng)輸入密碼");
String pwd=sca.next();
System.out.println("請(qǐng)?jiān)俅屋斎朊艽a");
String pwd1=sca.next();
if(pwd1.equals(pwd)){
name2=name;
pwd2=pwd;
System.out.println("注冊(cè)成功");
break;
}
else{
System.out.println("兩次密碼不一致,請(qǐng)重新輸入;是否重新注冊(cè)yes/no");
char regist=sca.next().charAt(0);
if(regist=='y'){
System.out.println("請(qǐng)重新輸入");
}
else if(regist=='n'){
System.out.println("您已經(jīng)退出注冊(cè)");
}
else{
System.out.println("您的輸入非法");
}
}
}
System.out.println("歡迎來(lái)到J18銀行");
System.out.println("請(qǐng)登錄:");
System.out.println("用戶名:");
username=sca.next();
System.out.println("密碼:");
String password=sca.next();
int num=queryAccount(username,password);
if(num==1){
System.out.println("登陸成功");
for(;;){
System.out.println("請(qǐng)選擇交易類型:");
System.out.println("1、存錢 2、取錢 3、查詢余額");
int cz=sca.nextInt();
if(cz==1){
cun();
}else if(cz==2){
qu();
}else if(cz==3){
query();
}else{
System.out.println("謝謝使用!");
break;
}
}
}else{
System.out.println("登錄失敗");
}
}
public static void cun() throws Exception{
System.out.println("請(qǐng)輸入你的存款金額:");
double money=sca.nextDouble();
String sql="update account set money=money+"+money;
boolean a=sc.execute(sql);
if(!a){
System.out.println("存款成功!");
}
}
public static void qu() throws Exception{
System.out.println("請(qǐng)輸入你的取款金額:");
double money=sca.nextDouble();
String sql="update account set money=money-"+money;
System.out.println(sql);
boolean a=sc.execute(sql);
if(!a){
System.out.println("取款成功!");
}
}
public static int queryAccount(String username,String password) throws Exception{
String sql="select * from account where aname='"+username+"'and apwd='"+password+"'";
ResultSet rs=sc.executeQuery(sql);
int num=0;
while(rs.next()){
num++;
}
return num;
}
public static void query() throws Exception{
String sql="select money from account where aname='"+username+"'";
ResultSet rs=sc.executeQuery(sql);
double money=0;
while(rs.next()){
money=rs.getDouble(1);
}
System.out.println("你的賬戶余額:"+money);
}
public static void getStatement() throws Exception{
Class.forName("com.mysql.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/atm";
String username="root";
String password="root";
Connection c=DriverManager.getConnection(url,username,password);
sc=c.createStatement();
}
}
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