PHP操做MYSQL--PDO

感受比直接弄SQL語句高級，但還不到ORM的封裝。

一步一步進化。

app.json

{
    "db": {
        "user": "root",
        "password": "xxxx",
        "host": "10.2.3.4",
        "port": "3306",
        "dbname": "bookstore"
    }
}

config.php

<?php

namespace Bookstore\Utils;

use Bookstore\Exceptions\NotFoundException;

require_once __DIR__ . '/NotFoundException.php';

class Config {
    private $data;
    //類靜態變量,保證變量惟一性
    private static $instance;
    
    //構造函數私有化,類外部不能夠調用.
    private function __construct() {
        $json = file_get_contents(__DIR__ . '/app.json');
        $this->data = json_decode($json, true);
    }
    
    //單例模式,保證只實例化一個類.
    public static function getInstance() {
        if (self::$instance == null) {
            //是能夠本身實例化本身的.
            self::$instance = new Config();
        }
        return self::$instance;
    }
    
    public function get($key) {
        if (!isset($this->data[$key])) {
            throw new NotFoundException("Key $key not in config.");
        }
        return $this->data[$key];
    }
}
?>

test.php

<?php
//使用命名空間,易於在大型應用中管理和組織php類.

use Bookstore\Utils\Config;

//命名空間能夠直接use,但若是這個命名空間沒有在標準約定位置,且沒有自動載入的話,須要使用require來手工定位一下.
require_once __DIR__ . '\Config.php';

header("content-type:text/html;charset=utf-8");
$dbConfig = Config::getInstance()->get("db");

$connStr = "mysql:host={$dbConfig['host']};port={$dbConfig['port']};dbname={$dbConfig['dbname']};charset=utf8";

$db = new \PDO($connStr,    $dbConfig['user'], $dbConfig['password']);
$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

$query = 'SELECT * FROM book WHERE author = :author';
$statement = $db->prepare($query);
$statement->bindValue('author', 'George Orwell');
$statement->execute();
$rows = $statement->fetchAll();
foreach ($rows as $row) {
    var_dump($row);
}
echo "<br/>";
$query = <<<SQL
INSERT INTO book(isbn, title, author, price)
VALUES(:isbn, :title, :author, :price)
SQL;
$statement = $db->prepare($query);
$params = [
    'isbn' => '9781413108614',
    'title' => 'Iliad',
    'author' => 'Homer',
    'price' => 9.25
];
$statement->execute($params);
$result = $db->exec($query);
echo $db->lastInsertId();
echo "<br/>";

function addBook(int $id, int $amount=1):void {
    $query = 'UPDATE book SET stock = stock + :n WHERE id = :id';
    $statement = $db->prepare($query);
    $statement->bindValue('id', $id);
    $statement->bindValue('n', $amount);
    
    if (!$statement->execute()) {
        throw new Exception($statement->errorInfo()[2]);
    }
}

function addSale($db, int $userId, array $bookIds):void {
    $db->beginTransaction();
    try {
        $query = 'INSERT INTO sale(customer_id, date)'
            . 'VALUES(:id, NOW())';
        $statement = $db->prepare($query);
        if (!$statement->execute(['id'=> $userId])) {
            throw new Exception($statement->errorInfo()[2]);
        }
        $saleId = $db->lastInsertId();
        
        $query = 'INSERT INTO sale_book(book_id, sale_id)'
            . 'VALUES(:book, :sale)';
        $statement = $db->prepare($query);
        $statement->bindValue('sale', $saleId);
        foreach ($bookIds as $bookId) {
            $statement->bindValue('book', $bookId);
            if (!$statement->execute()) {
                throw new Exception($statement->errorInfo()[2]);
            }
        }
        $db->commit();
    } catch (Exception $e) {
        $db->rollback();
        throw $e;
    }
}

try {
    addSale($db, 1, [1, 2, 300]);
} catch (Exception $e) {
    echo 'Error adding sale: ' . $e->getMessage();
}

try {
    addSale($db, 1, [1, 2, 3]);
} catch (Exception $e) {
    echo 'Error adding sale: ' . $e->getMessage();
}

    
?>

輸出

array(6) { ["id"]=> string(1) "1" ["isbn"]=> string(13) "9780882339726" ["title"]=> string(4) "1984" ["author"]=> string(13) "George Orwell" ["stock"]=> string(2) "12" ["price"]=> string(3) "8.7" } array(6) { ["id"]=> string(1) "3" ["isbn"]=> string(13) "9780736692427" ["title"]=> string(11) "Animal Farm" ["author"]=> string(13) "George Orwell" ["stock"]=> string(1) "8" ["price"]=> string(4) "4.06" } 
0
Error adding sale: Cannot add or update a child row: a foreign key constraint fails (`bookstore`.`sale_book`, CONSTRAINT `sale_book_ibfk_2` FOREIGN KEY (`book_id`) REFERENCES `book` (`id`))