From 333f1fa6398ad401f868a008db18338518d9dbcf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=92=9F=E6=A2=93=E9=91=AB?= <1813169067@qq.com>
Date: Sat, 20 May 2023 13:04:45 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BD=9C=E4=B8=9A?=
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+1. MySQL中创建一个数据库student_db
+
+2. 库中创建student表
+
+3. 表中数据如下
+
+4. | 编号 | 姓名 | 性别 |
+   | ---- | ---- | ---- |
+   | 1    | 张三 | 男   |
+   | 2    | 李四 | 女   |
+   | 3    | 王五 | 男   |
+
+   ~~~MySQL
+   create database student_db default char set utf8;
+   use student_db;
+   create table student_db  (
+       id int ,
+       name varchar(10),
+       sex char
+       );
+   insert into student_db values
+       (1,'张三','男'),
+       (2,'李四','女'),
+       (3,'王五','男');
+
+
+扩展题【预习题】
+
+能否实现一个类中，用四个方法来实现上面4个类的功能
+能否实现将查询的结果，封装成java对象
+import java.sql.*;
+
+public class Jdbc {
+    public static void main(String[] args) {
+        try {
+            select();//查询
+            update();//修改
+            insert();//添加
+            delete();//删除
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+
+    }
+    public static void select() throws SQLException, ClassNotFoundException {
+        //1.注册驱动
+        Class.forName("com.mysql.jdbc.Driver");
+        //2.获取连接对象
+        String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+        String username = "root";
+        String password = "root";
+        Connection conn = DriverManager.getConnection(url,username,password);
+        //3.定义SQL
+        String sql = "select * from sonyang;";
+
+        //4.获取执行SQL
+        Statement st = conn.createStatement();
+
+        //5.执行SQL
+        ResultSet rs = st.executeQuery(sql);
+        //6.处理返回结果
+        System.out.println("id      "+"name");
+        while (rs.next()){
+            int id = rs.getInt("id");
+            String name  = rs.getString("name");
+            System.out.println(id+"       "+name);
+        }
+        //7.释放资源
+        rs.close();
+        st.close();
+        conn.close();
+    }
+    public static void update() throws SQLException, ClassNotFoundException {
+        //1.注册驱动
+        Class.forName("com.mysql.jdbc.Driver");
+        //2.获取连接对象
+        String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+        String username = "root";
+        String password = "root";
+        Connection conn = DriverManager.getConnection(url,username,password);
+        //3.定义SQL
+        String sql = "update sonyang set name = '宋扬2号'where id=1";
+
+        //4.获取执行SQL
+        Statement st = conn.createStatement();
+
+        //5.执行SQL
+        int i = st.executeUpdate(sql);
+        //6.处理返回结果
+       if (i>0){
+           System.out.println("修改成功");
+       }else {
+           System.out.println("修改失败");
+       }
+        //7.释放资源
+        st.close();
+        conn.close();
+    }
+    public static void insert() throws ClassNotFoundException, SQLException {
+        //1.注册驱动
+        Class.forName("com.mysql.jdbc.Driver");
+        //2.获取连接对象
+        String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+        String username = "root";
+        String password = "root";
+        Connection conn = DriverManager.getConnection(url,username,password);
+        //3.定义SQL
+        String sql = "insert into sonyang values (2,'邓琪plus')";
+        //4.获取执行SQL
+        Statement st = conn.createStatement();
+
+        //5.执行SQL
+        int i = st.executeUpdate(sql);
+        //6.处理返回结果
+        if (i>0){
+            System.out.println("添加"+i+"行数据成功");
+        }else {
+            System.out.println("添加失败");
+        }
+        //7.释放资源
+        st.close();
+        conn.close();
+    }
+    public static void delete() throws ClassNotFoundException, SQLException {
+        //1.注册驱动
+        Class.forName("com.mysql.jdbc.Driver");
+        //2.获取连接对象
+        String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+        String username = "root";
+        String password = "root";
+        Connection conn = DriverManager.getConnection(url,username,password);
+        //3.定义SQL
+        String sql = "delete from sonyang where name='张三'";
+        //4.获取执行SQL
+        Statement st = conn.createStatement();
+        //5.执行SQL
+        int i = st.executeUpdate(sql);
+        //6.处理返回结果
+        if (i>0){
+            System.out.println("删除了"+i+"行数据成功");
+        }else {
+            System.out.println("删除失败");
+        }
+        //7.释放资源
+        st.close();
+        conn.close();
+
+    }
+}
\ No newline at end of file
-- 
Gitee