关于 php:PDO 执行不返回任何内容

PDO Execute Returns Nothing

假设我有一堂课：

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class pdoc {
private static $db_connect_pool;
public static function openConnect() {
try {
$connect_options_arr = array(PDO::ATTR_PERSISTENT => true);

self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''] = new PDO("".DB_DRIVER.":host=".DB_HOST.";db_name=".DB_NAME."", DB_USER, DB_PASS, $connect_options_arr);
} catch (Exception $e) {
print_r($e);
}
}

public static function getConnection() {
return self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''];
}

public static function qry($sql) {
self::openConnect();
$db_handle = self::getConnection();
$st_handle = $db_handle->prepare($sql);
return $st_handle->execute();
}
}

然后，调用类：

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$sql ="SELECT * FROM sometable";

if(pdoc::qry($sql)) echo"y";
else echo"n";

为什么代码总是返回n？我检查了已成功连接的连接，但是当我尝试执行一些查询时，它什么也没返回。有任何想法吗？谢谢。

更新(@Robbie 的代码)

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class pdoc {
private static $db_connect_pool;
public static function openConnect() {
try {
$connect_options_arr = array(PDO::ATTR_PERSISTENT => true, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);
self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''] = new PDO("".DB_DRIVER.":host=".DB_HOST.";db_name=".DB_NAME."", DB_USER, DB_PASS, $connect_options_arr);
} catch (Exception $e) {
print_r($e);
}
}

public static function getConnection() {
return self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''];
}

public static function qry($sql) {
self::openConnect();
$db_handle = self::getConnection();
try {
$st_handle = $db_handle->prepare($sql);
$retval = $st_handle->execute(); //--> Got error on this line
} catch (Exception $e) {
Die('Need to handle this error. $e has all the details');
}
return $retval;
}
}

错误提示：exception 'PDOException' with message 'SQLSTATE[3D000]: Invalid catalog name: 1046 No database selected'.

回答

变化：

1	... new PDO("".DB_DRIVER.":host=".DB_HOST.";db_name=".DB_NAME."", ...

进入：

1	... new PDO("".DB_DRIVER.":host=".DB_HOST.";dbname=".DB_NAME."", ...

在捕获错误消息(来自更新的代码)并参考此线程后，我发现 dbname 部分在我的代码中写为 dn_name 。因此，我将其更改为 dbname 并且效果很好！感谢@Robbie 提供您的代码！ :)

如果它什么都不返回，那么它失败了。您需要调用错误函数(errorInfo、errorCode)来找出原因。

但棘手的部分是你不知道错误是在数据库上还是在语句上，所以最好的技巧是使用异常错误报告，将所有函数package在一个 try catch 中，以及异常，当被困，将属于数据库或语句。更容易处理。

你的代码是：

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class pdoc {
private static $db_connect_pool;
public static function openConnect() {
try {
$connect_options_arr = array(PDO::ATTR_PERSISTENT => true, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);
self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''] = new PDO("".DB_DRIVER.":host=".DB_HOST.";db_name=".DB_NAME."", DB_USER, DB_PASS, $connect_options_arr);
} catch (Exception $e) {
print_r($e);
}
}

public static function getConnection() {
return self::$db_connect_pool[''.DB_DRIVER.'_'.DB_NAME.''];
}

public static function qry($sql) {
self::openConnect();
$db_handle = self::getConnection();
try {
$st_handle = $db_handle->prepare($sql);
$retval = $st_handle->execute();
} catch (Exception $e) {
Die('Need to handle this error. $e has all the details');
}
return $retval;
}
}