Day 42 (PHP)

1.header的用法

(1)画画时
指定画面Content-type网页输出，用image/jpeg型态

       header('Content-type: image/jpeg');

(2)输出转导向
输出转导向: 转去这个网站

       header("Location: brad44.html")

思考方式 http

<head>
    <meta charset="UTF-8">
     //这个文件内容(content-type)是这个(text/html)型态
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>

2.上传档案，等比例缩小 imagecopyresized(作业)

https://www.php.net/manual/en/function.imagecopyresized

3.PHP的相加

  • 数学相加
    . 字串相加

4.物件 ->的

$this->speed

5.物件：重点在属性，不是方法

　　class Bike{
    private $speed = 0;

    function upSpeed()
    {
        $this->speed = $this->speed < 1 ? 1 : $this->speed * 1.2;  //->的 
    }
    function downSpeed()
    {
        $this->speed = $this->speed < 1 ? 0 : $this->speed * 0.7;
    }
    function getSpeed()
    {
        return $this->speed;
    }
　　}

6.创物件

     $myBike = new Bike; //new 新创物件

7.物件 - 继承extends(好事发扬光大，坏事变更小)

若函式内甚麽都没写，会完全跟爸爸(Scooter)一样

    // Scooter is-a Bike
    class Scooter extends Bike{
    private $gear = 0;

    function chGear($gear = 0)
    {
        if ($gear >= 0 && $gear <= 7) {
            $this->gear = $gear;
        }
    }

    function upSpeed()
    {
        $this->speed = $this->speed < 1 ? 1 : $this->speed * ($this->gear * 1.2);
    }

    function dump()
    {
        var_dump($this);
    }
}

8.物件 - private

只能用在这个函式中，可以拿来使用，但不能继承extends

　　class Bike{
    private $speed = 0;

    function upSpeed()
    {
        $this->speed = $this->speed < 1 ? 1 : $this->speed * 1.2;  //->的 
    }
    function downSpeed()
    {
        $this->speed = $this->speed < 1 ? 0 : $this->speed * 0.7;
    }
    function getSpeed()
    {
        return $this->speed;
    }
　　}

开放继承子类别(一个子) - protected

    class Bike{
    // Bike has-a speed
    protected $speed = 0;  //protected

    // Bike has-a upSpeed()
    function upSpeed()
    {
        $this->speed = $this->speed < 1 ? 1 : $this->speed * 1.2;
    }
    function downSpeed()
    {
        $this->speed = $this->speed < 1 ? 0 : $this->speed * 0.7;
    }
    function getSpeed()  //辨识protected
    {
        return $this->speed;
    }
    }

都没有设定就是全部都可以继承用

9.建构式/建构子/建构方法/Constructor => 物件初始化

__construct进行属性的初始化
原本物件已存在，再进行属性的初始化(给定义)

   class Person
    {

    //属性,属性,属性
    private $name, $bike, $scooter;
    function __construct($name)
    {
    //定义属性
        $this->name = $name;
        $this->bike = new Bike;
        $this->scooter = new Scooter;
    }

    function getName()
    {
        return $this->name;
    }
    function getBike()
    {
        return $this->bike;
    }
    function getScooter()
    {
        return $this->scooter;
    }
}

10.MySQL - MySQLi

Abstraction Layers > 连接各家资料库来源(有整合的)
DBA — Database (dbm-style) Abstraction Layer
ODBC — ODBC (Unified) ===>整合各家程序语言系统(DSN)
PDO — PHP Data Objects

Vendor Specific Database Extensions > 直接连线各家的
CUBRID
dBase
Firebird/InterBase
FrontBase
IBM DB2 — IBM DB2, Cloudscape and Apache Derby
MongoDB — MongoDB driver
MySQL — MySQL Drivers and Plugins
OCI8 — Oracle OCI8
PostgreSQL
SQLite3
SQLSRV — Microsoft SQL Server Driver for PHP

https://www.php.net/manual/en/refs.database.php

MySQL 列表
https://www.php.net/manual/en/set.mysqlinfo.php

MySQLi MySQL的强化版
https://www.php.net/manual/en/book.mysqli.php

MySQLi > The mysqli class MySQL类别
https://www.php.net/manual/en/class.mysqli.php

MySQLi > The mysqli class > mysqli::__construct 连接特定资料库

11.PHP要写资料库时，要开MySQL

看看组态档brad02有没有支援到 MySQLi 外挂

12.建立 连结资料库MySQL

<?php
    $mysqli = new mysqli('127.0.0.1', 'root', 'root', 'class', 3306);  //建立SQL物件
    $mysqli->set_charset("utf8"); //编码

    //准备 要执行的SQL(抓好$sql的资料型态)
    $stmt = $mysqli->prepare($sql); //物件式
    //$stmt = mysqli_prepare($mysqli, $sql); //方法式

    $stmt->execute(); //执行SQL
?>

13.查看有无连线到资料库 var_dump()

    $mysqli = new mysqli('127.0.0.1', 'root', 'root', 'class', 3306);
    echo gettype($mysqli); //object0
    var_dump($mysqli);
    // object(mysqli)#1 (18) { 
    //     ["affected_rows"]=> int(0) 
    //     ["client_info"]=> string(13) "mysqlnd 7.4.1" 
    //     ["client_version"]=> int(70401) 
    //     ["connect_errno"]=> int(0) 
    ===>无错误 连线上

    //     ["connect_error"]=> NULL 
    //     ["errno"]=> int(0) 
    //     ["error"]=> string(0) "" 
    //     ["error_list"]=> array(0) { } 
    //     ["field_count"]=> int(0) 
    //     ["host_info"]=> string(20) "127.0.0.1 via TCP/IP" 
    //     ["info"]=> NULL 
    //     ["insert_id"]=> int(0) 
    //     ["server_info"]=> string(6) "5.7.24"  
    ===>Server version: 5.7.24 - MySQL Community Server (GPL)

    //     ["server_version"]=> int(50724) 
    //     ["sqlstate"]=> string(5) "00000" 
    //     ["protocol_version"]=> int(10) 
    //     ["thread_id"]=> int(5) 
    //     ["warning_count"]=> int(0) } 0

https://ithelp.ithome.com.tw/upload/images/20210807/20137684RHvABe7SWC.png

14.增加TABLE资料

prepare()是抓好$sql的资料型态，之後
bind_param 直接绑定 (必须按照INSERT INTO(DELETE、UPDATE..)顺序=======>重要)
execute()执行SQL
就可以放资料

    $sql = "INSERT INTO students (cName,cSex,cBirthday) VALUES (?,?,?,?)"; 
    //VALUES (?,?,?,?) 预先准备不要直接给

    //准备 要执行的SQL(抓好$sql的资料型态)
    $stmt = $mysqli->prepare($sql); //物件式

    $cName = 'Brad';
    $cSex = 'M';
    $cBirthday = '1999-01-02';
    $stmt->bind_param('sss', $cName, $cSex, $cBirthday); 
    //绑定参数bind_param(资料型态s字串 i整数)

必要给的资料要给，会自动递增的无须写入
https://ithelp.ithome.com.tw/upload/images/20210807/20137684lxyzo5SUEt.png

Q:为什麽 删掉後再新增的资料id不会递补前面被删号码??
A:自动递增是一个变数，只会前进不会後退
如果想要调整自动递增的值
查询:php mysql reset increment value
https://www.studentstutorial.com/php/autoincrement-reset.php

mysqli_query($conn,"ALTER TABLE category AUTO_INCREMENT = 1");

15.资料库语法 - 显示错误

https://www.php.net/manual/en/function.mysql-errno.php

    //错误讯息显示
    echo $mysqli->errno . '<br />'; //0 无错误
    echo $mysqli->error . '<br />';

16.删除TABLE资料

    $sql = "DELETE FROM students WHERE cID > ?";

    $stmt = $mysqli->prepare($sql);

    $delId = 10;  //cID 10号不要
    $stmt->bind_param('i', $delId); 
    $stmt->execute(); //执行SQL

17.修改TABLE资料

    //修改 UPDATE SET WHERE 条件式
    $sql = "UPDATE students SET ch =?, eng=?, math=? WHERE cID = ?";

    $stmt = $mysqli->prepare($sql);


    //修改45号
    $updateId = 45;
    $ch = rand(50, 80);
    $eng = rand(50, 80);
    $math = rand(50, 80);
    $stmt->bind_param('iiii', $ch, $eng, $math, $updateId);
    $stmt->execute(); //执行SQL

18.查询TABLE资料v_1(prepare版本)

选择的结果种类
mysqli_stmt — The mysqli_stmt class
https://www.php.net/manual/en/book.mysqli.php

     <?php
     $mysqli = new mysqli('127.0.0.1', 'root', 'root', 'class', 3306);
     $mysqli->set_charset("utf8");

     $sql = "SELECT cName,ch,eng,math FROM students";   //1.MySQL I 叙述句


     // 两种写法都一样 准备 要执行的SQL      //2.拿到MySQL I 叙述句
     $stmt = $mysqli->prepare($sql);
     //$stmt = mysqli_prepare($mysqli, $sql);
     

     $stmt->execute(); //执行SQL     //3.执行拿到MySQL I 叙述句

     $stmt->store_result();     //4.把结果储存

     echo $stmt->num_rows . '<br />';     //5.打开看 选择的结果

     $stmt->bind_result($v1, $v2, $v3, $v4);     //6.限定看哪几种资料
                                                 //bind_result查看资料的绑定参数，必须按照SELECT顺序
                
     while ($stmt->fetch())                      //7.一个一个抓出来看fetch()   
         echo "{$v1} : {$v2} : {$v3} : {$v4}<br />";
     }

19.查询TABLE资料v_2(阵列版本)

mysqli_query 制作成物件後，抓全部
https://www.php.net/manual/en/mysqli.query.php

看要出来甚麽值
https://www.php.net/manual/en/class.mysqli-result.php
阵列
https://www.php.net/manual/en/mysqli-result.fetch-array.php

     $mysqli = new mysqli('127.0.0.1', 'root', 'root', 'class', 3306);
     $mysqli->set_charset("utf8");

     //mysqli_query 制作成物件後，抓全部(物件) 2.MySQL I 叙述句
     $result = $mysqli->query('SELECT * FROM students '); 


     $row = $result->fetch_array();  //3. 看要出来甚麽值 用阵列的方式拿值

     //4.制作成回圈，让全部资料被抓取
     while ($rows = $result->fetch_array()) {                
         echo "{$rows['cID']} : {$rows['cName']} : {$rows['ch']}<br />";
       
     }

20.查询TABLE资料v_2(阵列版本)

mysqli_query 制作成物件後，抓全部
https://www.php.net/manual/en/mysqli.query.php

看要出来甚麽值
https://www.php.net/manual/en/class.mysqli-result.php
物件
https://www.php.net/manual/en/mysqli-result.fetch-object.php

     $mysqli = new mysqli('127.0.0.1', 'root', 'root', 'class', 3306);
     $mysqli->set_charset("utf8");
  
     $result = $mysqli->query('SELECT * FROM students '); // 2.MySQL I 叙述句

     $row = $result->fetch_object();  // 3.换成物件
     //$row = $result->fetch_array();

     // 4.全部抓出来
     while ($rows = $result->fetch_object()) {
         //物件抓法
         echo "{$rows->cID} : {$rows->cName}<br />";
         //echo "{$rows[0]} : {$rows[1]} : {$rows[7]}<br />";
     }

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