javaWeb第一次作业

数据库作业16个题

现在有一教学管理系统，具体的关系模式如下：

Student (no, name, sex, birthday, class)

Teacher (no, name, sex, birthday, prof, depart)

Course (cno, cname, tno)

Score (no, cno, degree)

其中表中包含如下数据：

Course表：

Score表：

Student表：

Teacher表：

根据上面描述完成下面问题：

（注意：注意保存脚本，尤其是DDL和DML，以便进行数据还原）

DDL

写出上述表的建表语句。

student表
create table student(
no int primary key,
name varchar(16),
sex char(6),
birthday varchar(32),
class int );
Teacher表
create table Teacher(
no int primary key auto_increment,
name varchar(16),
sex char(6),
birthday varchar(211),
prof varchar(21),
depart varchar(122));
course表
create table course(
cno int primary key auto_increment,
cname varchar(23),
tno int ));
score表
create table score(
no int primary key,
cno int ,
degree double(8,2));

命令：

DML

2,给出相应的INSERT语句来完成题中给出数据的插入。

    数据我放在我的C盘了    
       mysql> truncate table db1.teacher;
		Query OK, 0 rows affected (0.01 sec)

		mysql> select * from teacher;
		Empty set (0.01 sec)

		mysql> LOAD DATA  INFILE 'C:\db1_teacher.txt' INTO TABLE teacher;
		Query OK, 15 rows affected (0.01 sec)
      mysql> truncate table db1.score;
		Query OK, 0 rows affected (0.01 sec)

		mysql> select * from teacher;
		Empty set (0.01 sec)

		mysql> LOAD DATA  INFILE 'C:\db1_score.txt' INTO TABLE  score;
		Query OK, 15 rows affected (0.01 sec)
      mysql> truncate table db1.student;
		Query OK, 0 rows affected (0.01 sec)

		mysql> select * from student;
		Empty set (0.01 sec)

		mysql> LOAD DATA  INFILE 'C:\db1_teacher.txt' INTO TABLE student;
		Query OK, 15 rows affected (0.01 sec)
       mysql> truncate table db1.course;
		Query OK, 0 rows affected (0.01 sec)

		mysql> select * from course;
		Empty set (0.01 sec)

		mysql> LOAD DATA  INFILE 'C:\db1_teacher.txt' INTO TABLE course;
		Query OK, 15 rows affected (0.01 sec)

命令：

单表查询

3,以class降序输出student的所有记录（student表全部属性）

命令：

select * from student order by class desc;

4,列出教师所在的单位depart（不重复）。

命令：

Select distinct depart from teacher;

5,列出student表中所有记录的name、sex和class列

命令：

select name,sex,class from Student;

输出student中不姓王的同学的姓名。

命令：

Select name from student where name not like ‘王%’;

输出成绩为85或86或88或在60-80之间的记录（no,cno,degree）

命令：

select no,cno,degree from score where degree in(85,86,88) or degree between 60 and 80;

输出班级为95001或性别为‘女’ 的同学（student表全部属性）

命令：

select * from student where sex=’女’or class=95001;

以cno升序、degree降序输出score的所有记录。（score表全部属性）

命令：

select * from score order by degree desc,cno;

输出男生人数及这些男生分布在多少个班级中

命令：

select count(name),count(distinct class) from student where sex=’男’;

列出存在有85分以上成绩的课程编号。

命令：

select cno from score where degree>85;

输出95001班级的学生人数

命令：

select count(1) from student where class =95001;

输出‘3-105’号课程的平均分

命令：

select avg(degree) from Score where cno=’3-105’;

输出student中最大和最小的birthday日期值

命令：

select min(birthday),max(birthday) from student;

显示95001和95004班全体学生的全部个人信息（不包括选课）。（student表全部属性）

命令：

Select * from student where class in(95001,95004);

聚合查询

输出至少有5个同学选修的并以3开头的课程的课程号，课程平均分，课程最高分，课程最低分。

命令：

select cno,avg(degree),max(degree),min(degree)from Score inner Student on Score.no=Student.no group by cno having count(name)>5;

作业2：

import java.sql.*;

public class JDBCTest {
    /**
     * 1.使用DriverManager 进行加载驱动 Driver
     * 2.通过驱动的加载拿到连接对象 Connection
     * 3.通过connection对象获取到 Statement
     * 4.使用Statement对象 进行sql查询或更新
     * 5.查询执行完一定会拿到一个结果
     * 6.关闭资源（）
     *
     */
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //1,加载驱动
       Class.forName("com.mysql.jdbc.Driver");
       //2,获取连接的对象
        Connection conn =      DriverManager.getConnection("jdbc:mysql://localhost:3306/db1","admin","DEFdef123!");
        //3,获取statement对象
        Statement st =conn.createStatement();
        //4,进行查询，返回结果集
        ResultSet rs =st.executeQuery("select * from tb4");
        //5,对结果进行遍历
        while(rs.next()){
                 System.out.println(rs.getString("user_name")+":"+rs.getInt("id")+":"+rs.getInt("pid")+":"+rs.getString("age"));
        }
        //6,关闭连接
        rs.close();
               st.close();
              conn.close();

    }
}

JDBC封装
封装
public class JDBCUtils {
    private static String driver ="com.mysql.jdbc.Driver";
    private  static String url="jdbc:mysql://localhost:3306/db1";
    private static String username="admin";
    private static String password ="DEFdef123!";
    private static Connection conn;
    private static Statement ts;
    private static ResultSet rs;
    static {
    try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    //封装连接
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,username,password);
    }
     //封装关闭
    public static void jdbcClose(ResultSet rs,Statement st ,Connection  conn) throws SQLException {
        rs.close();
        if(rs!=null){
            rs=null;
        }
        st.close();
        if(st!=null){
            st=null;
        }
        conn.close();
        if(conn!=null){
            conn=null;
        }

    }

}
查询封装
//查询封装
public static List  select(String sql,User user) throws SQLException {
    List<User> list =new ArrayList<>();
    conn= getConnection();
    ts =conn.createStatement();
    ResultSet rs =ts.executeQuery(sql);
    while(rs.next()){
        user.setId(rs.getInt("id"));
        user.setUsername(rs.getString("username"));
        user.setPassword(rs.getString("password"));
    }
    list.add(user);
    jdbcClose(rs,ts,conn);
    return list;

}

查询封装后的测试：
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) throws SQLException{
       Scanner input =new Scanner(System.in);
       System.out.println("请输入用户名");
        String username =input.next();
        System.out.println("请输入密码");
        String password =input.next();
        String sql ="select * from user";
        User u =new User();
        ArrayList l =(ArrayList) JDBCUtils.select(sql,u);
        u=(User)l.get(0);
        System.out.println(u);
        if(username==u.getUsername()&&password==u.getPassword()){
            System.out.println("登录成功");
        }
        else{
            System.out.println("登录失败，请重新输入");
        }
        }

    }
User实体类
public class User {
    private String username;
    private int id;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", id=" + id +
                ", password='" + password + '\'' +
                '}';
    }
}

增删改封装
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class JDBCUtils {
    private static String driver ="com.mysql.jdbc.Driver";
    private  static String url="jdbc:mysql://localhost:3306/db1";
    private static String username="admin";
    private static String password ="DEFdef123!";
    private static Connection conn;
    private static Statement ts;
    private static ResultSet rs;
    static {
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    //封装连接
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,username,password);
    }
    //增增删改封装
   public static void update(String sql) throws SQLException {
        conn= getConnection();
        ts =conn.createStatement();
        int bSet =ts.executeUpdate(sql);
        System.out.println(bSet);
        jdbcClose(ts,conn);
    }

    private static void jdbcClose(Statement ts, Connection conn) throws SQLException {
                 ts.close();
                 if(ts!=null){
                     ts=null;
                 }
                 conn.close();
                 if(conn!=null){
                     conn=null;
                 }
    }

    //封装关闭
    public static void jdbcClose(ResultSet rs,Statement st ,Connection conn) throws SQLException {
        rs.close();
        if(rs!=null){
            rs=null;
        }
        st.close();
        if(st!=null){
            st=null;
        }
        conn.close();
        if(conn!=null){
            conn=null;
        }

    }

}
增删改测试：
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Test {
    public static void main(String[] args) throws SQLException{
       String sql ="insert into tb4 values('wangxing4',6,7,'22')";
       JDBCUtils.update(sql);
    }
}
查询单元测试
  @Test
    public void select() throws SQLException {
        String sql ="select * from tb4";
        JDBCUtils.select(sql);
    }
}

查询单元测试
import org.junit.Test;

import java.sql.SQLException;

import static org.junit.Assert.*;

public class TestTest {

    @Test
    public void update() throws SQLException {
        String sql ="insert into  tb4 values('wangxing5',8,9,'34')";
        JDBCUtils.update(sql);
    }
}

作业3：

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class JDBCUtils {
    private static String driver ="com.mysql.jdbc.Driver";
    private  static String url="jdbc:mysql://localhost:3306/db1";
    private static String username="admin";
    private static String password ="DEFdef123!";
    private static Connection conn;
    private static Statement ts;
    private static ResultSet rs;
    static {
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    //封装连接
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,username,password);
    }
    //查询增删改
    public static void update(String sql) throws SQLException {
        conn= getConnection();
        ts =conn.createStatement();
        int bSet =ts.executeUpdate(sql);
        System.out.println(bSet);
        jdbcClose(ts,conn);
    }
    //查询封装
    public static List  select(String sql,User user) throws SQLException {
        List<User> list =new ArrayList<>();
        conn= getConnection();
        ts =conn.createStatement();
        ResultSet rs =ts.executeQuery(sql);
        while(rs.next()){
            user.setId(rs.getInt("id"));
            user.setUsername(rs.getString("username"));
            user.setPassword(rs.getString("password"));
        }
        list.add(user);
        jdbcClose(rs,ts,conn);
        return list;

    }

    private static void jdbcClose(Statement ts, Connection conn) throws SQLException {
                 ts.close();
                 if(ts!=null){
                     ts=null;
                 }
                 conn.close();
                 if(conn!=null){
                     conn=null;

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