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PDO与MySQLi各自优势及该如何选择

下文主要给大家带来PDO与MySQLi各自优势及该如何选择,希望这些内容能够带给大家实际用处,这也是我编辑PDO与MySQLi各自优势及该如何选择这篇文章的主要目的。好了,废话不多说,大家直接看下文吧。

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PDO的优势

1.有用的获取方式

2.允许直接将变量和值传递给execute

3.能够自动检测变量类型(实际发生的情况是,发送到云服务器时,所有内容都被视为字符串,但被转换为正确的类型。这在预处理语句中100%有效,但在某些边缘情况下无效,比如在模拟模式中。)

4.提供一个选项,使用预处理语句自动缓冲结果

5.命名参数(尽管在PDO中关闭模拟模式是无用的,因为你只能使用相同的名称一次)

MySQLi优势

1.异步查询

2.获取有关受影响行的更多信息的能力,比如更新具有相同值的行(可以在PDO中作为构造函数设置完成,以后无法更改)

3.正确的数据库关闭方法

4.一次多个查询(如果在PDO中打开模拟模式,则可以)

5.使用持久连接自动清除

代码的差异

PDO和MySQLi非常相似,但是在语法上略有不同。MySQLi遵循旧式的PHP snake_case约定,而PDO使用camelCase。此外,MySQLi的方法被用作对象属性,而PDO对函数使用传统语法。

PDO和MySQLi都要求你使用两个单独的方法来使用预处理语句,从而使事情变得复杂。不过PDO消除了使用专用绑定函数的需要。

例如,在特定于供应商的PostgreSQL API中,你可以这样做。

下面是一个示例,演示如何执行一个“non-prepared”查询来获取一个包含MySQLi和PDO的关联数组,以供参考。

$arr = $mysqli->query("SELECT * FROM myTable")->fetch_all(MYSQLI_ASSOC);
$arr = $pdo->query("SELECT * FROM myTable")->fetchAll(PDO::FETCH_ASSOC);

实际上,最好的方法是使用包装器、查询生成器或ORM。虽然PDO可以直接将值绑定到execute中,但它仍然不是理想的。在我创建的类中,你可以链接所有调用,同时传入值作为参数参数绑定。

$arr = $mysqli->query("SELECT * FROM myTable WHERE id > ?", [12])->fetchAll('assoc');

现在,在变量中以更简洁的方式存储了整个关联数组。

创建一个新的数据库连接

PDO

$dsn = "mysql:host=localhost;dbname=myDatabase;charset=utf8mb4";$options = [
  PDO::ATTR_EMULATE_PREPARES   => false, // turn off emulation mode for "real" prepared statements
  PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION, //turn on errors in the form of exceptions
  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, //make the default fetch be an associative array];try {
  $pdo = new PDO($dsn, "username", "password", $options);} catch (Exception $e) {
  error_log($e->getMessage());
  exit('Something weird happened'); //something a user can understand}

MySQLi

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);try {
  $mysqli = new mysqli("localhost", "username", "password", "databaseName");
  $mysqli->set_charset("utf8mb4");} catch(Exception $e) {
  error_log($e->getMessage());
  exit('Error connecting to database'); //Should be a message a typical user could understand}

插入、更新、删除

PDO

$stmt = $pdo->prepare("INSERT INTO myTable (name, age) VALUES (?, ?)");
$stmt->execute([$_POST['name'], 29]);
$stmt = null;

MySQLi

$stmt = $mysqli->prepare("UPDATE myTable SET name = ? WHERE id = ?");
$stmt->bind_param("si", $_POST['name'], $_SESSION['id']);
$stmt->execute();
$stmt->close();

注意,使用PDO可以将prepare()和execute()链接起来。

获取受影响的行数

PDO

$stmt->rowCount();

MySQLi

$stmt->affected_rows;

插入最新的主键

注意,这两种方法都使用connection变量,而不是$stmt。

PDO

$pdo->lastInsertId();

MySQLi

$mysqli->insert_id;

得到匹配的行

PDO

在PDO中,实现这一点的唯一方法是将其设置为一个连接选项,以更改rowCount()的行为。这意味着rowCount()将为整个数据库连接返回匹配的行或更改的行,但不能同时返回两者。

$options = [
  PDO::MYSQL_ATTR_FOUND_ROWS => true];

MySQLi

$mysqli->info;

这将输出整个字符串的信息,如:

Rows matched: 1 Changed: 0 Warnings: 0

可以这样做

preg_match_all('/(\S[^:]+): (\d+)/', $mysqli->info, $matches); 
$infoArr = array_combine ($matches[1], $matches[2]);
var_export($infoArr);

现在可以很容易地访问这些值。注意,该值是一个字符串,因此你可以将所有值转换为int,===可以使用,也可以严格检查==。

['Rows matched' => '1', 'Changed' => '0', 'Warnings' => '0']

抓取

获取关联数组

PDO

$stmt = $pdo->prepare("SELECT * FROM myTable WHERE id <= ?");
$stmt->execute([5]);
$arr = $stmt->fetchAll(PDO::FETCH_ASSOC);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;

MySQLi

$stmt = $mysqli->prepare("SELECT id, name, age FROM myTable WHERE name = ?");
$stmt->bind_param("s", $_POST['name']);
$stmt->execute();
$arr = $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

获取单行

PDO

$stmt = $pdo->prepare("SELECT id, name, age FROM myTable WHERE name = ?");
$stmt->execute([$_POST['name']]);
$arr = $stmt->fetch(PDO::FETCH_ASSOC);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;

MySQLi

$stmt = $mysqli->prepare("SELECT id, name, age FROM myTable WHERE name = ?");
$stmt->bind_param("s", $_POST['name']);
$stmt->execute();
$arr = $stmt->get_result()->fetch_assoc();
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

获取单个值(标量)

PDO

$stmt = $pdo->prepare("SELECT id, name, age FROM myTable WHERE name = ?");
$stmt->execute([$_POST['name']]);
$arr = $stmt->fetch(PDO::FETCH_COLUMN);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;

MySQLi

$stmt = $mysqli->prepare("SELECT id, name, age FROM myTable WHERE name = ?");
$stmt->bind_param("s", $_POST['name']);
$stmt->execute();
$arr = $stmt->get_result()->fetch_row()[0];
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

获取对象数组

PDO

class myClass {}
$stmt = $pdo->prepare("SELECT name, age, weight FROM myTable WHERE name = ?");
$stmt->execute(['Joe']);
$arr = $stmt->fetchAll(PDO::FETCH_CLASS, 'myClass');
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;

MySQLi

class myClass {}
$arr = [];
$stmt = $mysqli->prepare("SELECT id, name, age FROM myTable WHERE id = ?");
$stmt->bind_param("s", $_SESSION['id']);
$stmt->execute();
$result = $stmt->get_result();
while($row = $result->fetch_object('myClass')) {
  $arr[] = $row;
}
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

正如你所看到的,PDO在这里非常出色。MySQLi没有像$mysqli_result->fetch_all(MYSQLI_OBJ)这样的东西。PDO甚至更进一步,通过使用fetchAll(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, 'myClass')对它进行位元化,以处理在类构造函数之后调用它的默认行为。可以在MySQLi中复制这种行为,但是它依赖于省略构造函数,和魔术方法 _set(),或者只在构造函数中设置它(如果它不等于默认值)。

PDO

$search = "%{$_POST['search']}%";
$stmt = $pdo->prepare("SELECT id, name, age FROM myTable WHERE name LIKE ?");
$stmt->execute([$search]);
$arr = $stmt->fetchAll();
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;
Copy

MySQLi

$search = "%{$_POST['search']}%";
$stmt = $mysqli->prepare("SELECT id, name, age FROM myTable WHERE name LIKE ?"); 
$stmt->bind_param("s", $search);
$stmt->execute();
$arr = $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

获取模式

到目前为止,这是我最喜欢的PDO特性。PDO中的获取模式非常有用,而MySQLi还没有添加它们。

获取键/值对

PDO

$stmt = $pdo->prepare("SELECT event_name, location FROM events WHERE id < ?");
$stmt->execute([25]);
$arr = $stmt->fetchAll(PDO::FETCH_KEY_PAIR);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;
Copy

MySQLi

$arr = [];
$id = 25;
$stmt = $con->prepare("SELECT event_name, location FROM events WHERE id < ?");
$stmt->bind_param("i", $id);
$stmt->execute();
$result = $stmt->get_result();
while($row = $result->fetch_row()) {
  $arr[$row[0]] = $row[1];
}
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();

输出:

['Cool Event' => 'Seattle', 'Fun Event' => 'Dallas', 'Boring Event' => 'Chicago']

获取组列

PDO

$stmt = $pdo->prepare("SELECT hair_color, name FROM myTable WHERE id < ?");
$stmt->execute([10]);
$arr = $stmt->fetchAll(PDO::FETCH_GROUP | PDO::FETCH_COLUMN);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;
Copy

MySQLi

$arr = [];
$id = 10;
$stmt = $con->prepare("SELECT hair_color, name FROM myTable WHERE id < ?");
$stmt->bind_param("i", $id);
$stmt->execute();
$result = $stmt->get_result();
while($row = $result->fetch_row()) {
  $arr[$row[0]][] = $row[1];
}
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();
Copy

输出:

[
  'blonde' => ['Patrick', 'Olivia'],
  'brunette' => ['Kyle', 'Ricky'],
  'red' => ['Jordan', 'Eric']
]

获取键/值对数组

PDO

$stmt = $pdo->prepare("SELECT id, max_bench, max_squat FROM myTable WHERE weight < ?");
$stmt->execute([200]);
$arr = $stmt->fetchAll(PDO::FETCH_UNIQUE);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;
Copy

MySQLi

$arr = [];
$weight = 200;
$stmt = $con->prepare("SELECT id, max_bench, max_squat FROM myTable WHERE weight < ?");
$stmt->bind_param("i", $weight);
$stmt->execute();
$result = $stmt->get_result();
$firstColName = $result->fetch_field_direct(0)->name;
while($row = $stmtResult->fetch_assoc()) {
  $firstColVal = $row[$firstColName];
  unset($row[$firstColName]);
  $arr[$firstColVal] = $row;
}
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();
Copy

输出:

[
  17 => ['max_bench' => 230, 'max_squat' => 175],
  84 => ['max_bench' => 195, 'max_squat' => 235],
  136 => ['max_bench' => 135, 'max_squat' => 285]
]

获取组

PDO

$stmt = $pdo->prepare("SELECT hair_color, name, age FROM myTable WHERE id < ?");
$stmt->execute([12]);
$arr = $stmt->fetchAll(PDO::FETCH_GROUP);
if(!$arr) exit('No rows');
var_export($arr);
$stmt = null;
Copy

MySQLi

$arr = [];
$id = 12;
$stmt = $con->prepare("SELECT hair_color, name, age FROM myTable WHERE id < ?");
$stmt->bind_param("i", $id);
$stmt->execute();
$result = $stmt->get_result();
$firstColName = $result->fetch_field_direct(0)->name;
while($row = $stmtResult->fetch_assoc()) {
  $firstColVal = $row[$firstColName];
  unset($row[$firstColName]);
  $arr[$firstColVal][] = $row;
}
if(!$arr) exit('No rows');
var_export($arr);
$stmt->close();
Copy

输出:

[
  'blonde' => [
    ['name' => 'Patrick', 'age' => 22],
    ['name' => 'Olivia', 'age' => 18]
  ],
  'brunette'  => [
    ['name' => 'Kyle', 'age'=> 25],
    ['name' => 'Ricky', 'age' => 34]
  ],
   'red'  => [
    ['name' => 'Jordan', 'age' => 17],
    ['name' => 'Eric', 'age' => 52]
  ]
]

在数组中的位置

PDO

$inArr = [1, 3, 5];
$clause = implode(',', array_fill(0, count($inArr), '?')); 
$stmt = $pdo->prepare("SELECT * FROM myTable WHERE id IN ($clause)");
$stmt->execute($inArr);
$resArr = $stmt->fetchAll();
if(!$resArr) exit('No rows');
var_export($resArr);
$stmt = null;
Copy

MySQLi

$inArr = [12, 23, 44];
$clause = implode(',', array_fill(0, count($inArr), '?')); /
$types = str_repeat('i', count($inArr)); /
$stmt = $mysqli->prepare("SELECT id, name FROM myTable WHERE id IN ($clause)");
$stmt->bind_param($types, ...$inArr);
$stmt->execute();
$resArr = $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
if(!$resArr) exit('No rows');
var_export($resArr);
$stmt->close();

与其他占位符一起排列的位置

PDO

$inArr = [1, 3, 5];
$clause = implode(',', array_fill(0, count($inArr), '?')); 
$stmt = $pdo->prepare("SELECT * FROM myTable WHERE id IN ($clause) AND id < ?");
$fullArr = array_merge($inArr, [5]); 
$stmt->execute($fullArr);
$resArr = $stmt->fetchAll();
if(!$resArr) exit('No rows');
var_export($resArr);
$stmt = null;
Copy

MySQLi

$inArr = [12, 23, 44];
$clause = implode(',', array_fill(0, count($inArr), '?'));
$types = str_repeat('i', count($inArr));
$types .= 'i'; //add 1 more int type
$fullArr = array_merge($inArr, [26]); 
$stmt = $mysqli->prepare("SELECT id, name FROM myTable WHERE id IN ($clause) AND age > ?");
$stmt->bind_param($types, ...$fullArr); 
$stmt->execute();
$resArr = $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
if(!$resArr) exit('No rows');
var_export($resArr);
$stmt->close();

交易

PDO

try {
  $pdo->beginTransaction();
  $stmt1 = $pdo->prepare("INSERT INTO myTable (name, state) VALUES (?, ?)");
  $stmt2 = $pdo->prepare("UPDATE myTable SET age = ? WHERE id = ?");
  if(!$stmt1->execute(['Rick', 'NY'])) throw new Exception('Stmt 1 Failed');
  else if(!$stmt2->execute([27, 139])) throw new Exception('Stmt 2 Failed');
  $stmt1 = null;
  $stmt2 = null;
  $pdo->commit();
} catch(Exception $e) {
  $pdo->rollback();
  throw $e;
}

MySQLi

try {
  $mysqli->autocommit(FALSE);
  $stmt1 = $mysqli->prepare("INSERT INTO myTable (name, age) VALUES (?, ?)");
  $stmt2 = $mysqli->prepare("UPDATE myTable SET name = ? WHERE id = ?");
  $stmt1->bind_param("si", $_POST['name'], $_POST['age']);
  $stmt2->bind_param("si", $_POST['name'], $_SESSION['id']);
  $stmt1->execute();
  $stmt2->execute();
  $stmt1->close();
  $stmt2->close();
  $mysqli->autocommit(TRUE);
} catch(Exception $e) {
  $mysqli->rollback(); 
  throw $e;
}

MySQLi有一个问题,但是解决方案是使用全局处理程序将错误转换为异常。

命名为Paramters

$stmt = $pdo->prepare("UPDATE myTable SET name = :name WHERE id = :id");
$stmt->execute([':name' => 'David', ':id' => 3]);
$stmt = null;

对于以上关于PDO与MySQLi各自优势及该如何选择,大家是不是觉得非常有帮助。如果需要了解更多内容,请继续关注我们的行业资讯,相信你会喜欢上这些内容的。


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