视频地址：哔哩哔哩

讲义作业飞书地址：day06作业

基础性作业，加油！

1、SQL语句的编写

-- 1. 查询所有的性别为男(gender 为 1)的 讲师 (job 为 2) , 并根据入职时间, 对员工进行升序排序
select * from emp where gender = 1 and job = 2 order by entry_date asc;

-- 2. 根据 入职时间 对公司的员工进行 升序排序 ， 入职时间相同 , 再按照 ID 进行降序排序
select * from emp order by entry_date asc,id desc;

-- 3. 查询性别为男(gender 为 1) 且 薪资大于 6000 的员工, 并根据 入职时间 对公司的员工进行 升序排序 ， 入职时间相同 , 再按照 ID 进行降序排序
select * from emp where gender = 1 and salary > 6000 order by entry_date asc ,id desc ;

-- 4. 查询性别为男(gender 为 1)的员工 且 在 '2005-10-01' 至 '2018-10-01' 之间入职的员工, 并根据 入职时间 对公司的员工进行 升序排序 ， 入职时间相同 , 再按照 ID 进行降序排序
select * from emp where gender = 1 and (entry_date between '2005-10-01' and '2018-10-01') order by entry_date asc ,id desc;

-- 5. 查询姓 '阮' 且 在 '2010-10-01' 之后入职的员工, 并根据入职时间进行升序排序, 并对结果分页操作, 展示第1页员工数据, 每页展示5条记录
select * from emp where name like '阮%' and entry_date > '2010-10-01' order by entry_date asc limit 5;

2、通过JDBC程序，基于预编译SQL，执行更新操作

@Test
    public void testUpdate() throws ClassNotFoundException, SQLException {
        //1.注册驱动
        Class.forName("com.mysql.cj.jdbc.Driver");
        //2.获取数据库连接
        String url = "jdbc:mysql://localhost:3306/web01";
        String username = "root";
        String password = "moon";

        String sql = "update user set password = ?, name = ?, age = ? where id = ?";
        PreparedStatement ps = DriverManager.getConnection(url, username, password).prepareStatement(sql);
        ps.setString(1,"haveagoodluck");
        ps.setString(2,"关羽");
        ps.setInt(3,32);
        ps.setInt(4,4);
        int i = ps.executeUpdate();
        System.out.println(i);
        ps.close();
    }

3、通过JDBC程序，基于预编译SQL，执行查询语句

@Test
    public void select() throws ClassNotFoundException, SQLException {
        //1.注册驱动
        Class.forName("com.mysql.cj.jdbc.Driver");
        //2.获取数据库连接
        String url = "jdbc:mysql://localhost:3306/web01";
        String username = "root";
        String password = "moon";

        String sql = "select id,username,password,name,age from user where age >= ? and id <= ?";
        PreparedStatement ps = DriverManager.getConnection(url, username, password).prepareStatement(sql);
        ps.setInt(1,20);
        ps.setInt(2,4);

        ResultSet rs = ps.executeQuery();
        while (rs.next()) {
            User user = new User(
                    rs.getInt("id"),
                    rs.getString("username"),
                    rs.getString("password"),
                    rs.getString("name"),
                    rs.getInt("age")
            );
            System.out.println(user);
        }
        rs.close();
        ps.close();
    }

4、导入项目，基于Mybatis完成SQL语句实现

①导入项目：将文件解压后放在目录里，然后导入xml文件

②创建数据库，创建表

③实现SQL语句（注意更改数据库连接信息，密码更改为自己的，url更改为对应数据库）

• StudentMapper.java

package com.itheima.mapper;

import com.itheima.pojo.Student;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

@Mapper
public interface StudentMapper {
    @Select("select * from student")
    public List<Student> findAll();

    @Insert("insert into student values(null,#{name},#{no},#{gender},#{phone},#{idCard},#{degree},#{graduationDate},#{createTime},#{updateTime})")
    public void insert(Student s);

    @Update("update student set no = #{no}, phone = #{phone}, id_card = #{idCard} where id = #{id}")
    public void update(Student s);

    //下面两个基于XML配置SQL
    public Student findById(Integer id);

    public void deleteById(Integer id);

}

• StudentMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.StudentMapper">
    <!--resultType：查询返回的单条记录所封装的类型-->
    <select id="findById" resultType="com.itheima.pojo.Student">
        select * from student where id = #{id}
    </select>
    <select id="deleteById" resultType="com.itheima.pojo.Student">
        delete from student where id = #{id}
    </select>

</mapper>

• SpringBootMybatisApplicationTests.java

package com.itheima;

import com.itheima.mapper.StudentMapper;
import com.itheima.pojo.Student;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class SpringBootMybatisApplicationTests {
    @Autowired
    public StudentMapper studentMapper;

    @Test
    public void testFindAll(){
        studentMapper.findAll().forEach(System.out::println);
    }

    @Test
    public void testInsert(){
        Student s = new Student(null, "小明", "2019011", 1, "13888888888", "123456789012345678", 1, null, null, null);
        studentMapper.insert(s);
    }

    @Test
    public void testUpdate(){
        Student s = new Student(12, "小明", "2019012", 1, "13888889998", "123456789012345789", 1, null, null, null);
        studentMapper.update(s);
    }

    @Test
    public void testFindById(){
        System.out.println(studentMapper.findById(5));
    }

    @Test
    public void testDeleteById(){
        studentMapper.deleteById(7);
    }

}

有问题可以私信我或者评论~