PDOStatement::setFetchMode

(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.2.0)

PDOStatement::setFetchMode — 为语句设置默认的获取模式

说明

public PDOStatement::setFetchMode(int $mode): bool

public PDOStatement::setFetchMode(int $mode = PDO::FETCH_COLUMN, int $colno): bool

public PDOStatement::setFetchMode(int $mode = PDO::FETCH_CLASS, string $class, ?array $constructorArgs = null): bool

public PDOStatement::setFetchMode(int $mode = PDO::FETCH_INTO, object $object): bool

参数

mode: 获取模式必须是 PDO::FETCH_* 系列常量中的一个。
colno: 列号。
class: 类名。
constructorArgs: 构造方法参数。
object: 对象。

返回值

成功时返回 true，或者在失败时返回 false。

示例

示例 #1 设置获取模式

以下示例演示了 PDOStatement::setFetchMode() 如何更改 PDOStatement 对象的默认获取模式。

<?php
$stmt = $dbh->query('SELECT name, colour, calories FROM fruit');
$stmt->setFetchMode(PDO::FETCH_NUM);
foreach ($stmt as $row) {
    print $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
}

以上示例的输出类似于：

 
apple   red     150
banana  yellow  250
orange  orange  300
kiwi    brown   75
lemon   yellow  25
pear    green   150

＋add a note

User Contributed Notes 5 notes

down

Dormilich at netscape dot net ¶

13 years ago

if you want to fetch your result into a class (by using PDO::FETCH_CLASS) and want the constructor to be executed *before* PDO assings the object properties, you need to use the PDO::FETCH_PROPS_LATE constant:

<?php
$stmt = $pdo->prepare("your query");

$stmt->setFetchMode(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE, "className", $constructorArguments);

# pass parameters, if required by the query
$stmt->execute($parameters);

foreach ($stmt as $row)
{
    // do something with (each of) your object
}
?>

down

Kats ¶

6 years ago

Something very helpful is knowing how to access namespaces from the function. It took me a minute (and Google) to figure out. The ::class property is going to be your best friend in this case.

<?php
$stmt->setFetchMode(PDO::FETCH_CLASS, Name\Space\Class::class);
?>

down

stein_AT_rhrk.uni-kl.de ¶

15 years ago

Some note on PDO :: FETCH_CLASS | PDO :: FETCH_CLASSTYPE

It took me some time, to realize, that you can not use this fetch-mode in $stm->setFetchMode(), when you want to retrieve objects from the database whereas the type is defined by the first column in the resultset.
You have to define this mode directly in the $stm->fetch() method.

To make it clearer:

$stm = $pdo->query("SELECT * FROM `foo`);
$stm->setFetchMode(FETCH_CLASS | PDO :: FETCH_CLASSTYPE);

$object = $stm->fetch();

Will not return the expected object, whereas

$stm = $pdo->query("SELECT * FROM `foo`");

$object = $stm->fetch(FETCH_CLASS | PDO :: FETCH_CLASSTYPE);

will give you the object of the class, defined in the first column of `foo`.

down

-5

Dariusz Kielar ¶

17 years ago

PDO::FETCH_CLASS may be used only with this method and it takes up to three parameters then:
 - int mode
 - string className
 - array constructorArgs (optional)

<?php
$stmt = $pdo -> query('your query');
$stmt -> setFetchMode(PDO::FETCH_CLASS, 'yourClass', array(0 => false));

while($row = $stmt -> fetch())
{
   // $row is an object of "yourClass" class
}
$stmt -> closeCursor();
?>

Note also that the constructor is called AFTER the data is set on the object.

down

-6

matt at kynx dot org ¶

17 years ago

To fetch the rows into an existing instance of a class, use PDO::FETCH_INTO and pass the object as the second parameter. 

The class _must_ have the column names declared as public members, or the script will die. But overloading with __set() and __get() lets it handle any column your query throws at it.  

Set the fetch mode right after you call prepare(). It appears you _must_ use execute() - fetch() won't work. A small example, adapted from ext/pdo/tests/pdo_025.phpt:

<?php
class Test
{
    protected $cols;
    
    function __set($name, $value) {
        $this->cols[$name] = $value;
    }
    
    function __get($name) {
        return $this->cols[$name];
    }
}

$obj = new Test();
$db = PDOTest::factory();
$stmt = $db->prepare("select * from test");
$stmt->setFetchMode(PDO::FETCH_INTO, $obj);
$stmt->execute();

foreach ($stmt as $a) {
    print_r($a);
}

print_r($obj); // contains the same values as the last iteration above
?>

＋add a note