php-使用PDO查询代替mysql,即已弃用

众所周知,PHP v7.0中已删除了MysqL,我正在尝试使用pdo使用以下示例通过数据表获取数据(服务器端)(但在MysqL中需要使用pdo)：
码：

列：

/* Array of database columns which should be read and sent back to DataTables. Use a space where
 * you want to insert a non-database field (for example a counter or static image)
 */
$aColumns = array( 'first_name', 'last_name', 'position', 'office', 'salary' );

/* Indexed column (used for fast and accurate table cardinality) */
$sIndexColumn = "id";

/* DB table to use */
$sTable = "datatables_demo";

创建PDO连接：

$db_host = "localhost";
$db_name = "sadad";
$db_user = "root";
$db_pass = "root";

try{
    $db_con = new PDO("MysqL:host={$db_host};dbname={$db_name}",$db_user,$db_pass);
    $db_con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e){
    echo $e->getMessage();
}

以下代码：

$sLimit = "";
if ( isset( $_GET['idisplayStart'] ) && $_GET['idisplayLength'] != '-1' )
{
    $sLimit = "LIMIT ".$db_con->quote( $_GET['idisplayStart'] ).", ".
        $db_con->quote( $_GET['idisplayLength'] );
}


/*
 * Ordering
 */
if ( isset( $_GET['iSortCol_0'] ) )
{
    $sOrder = "ORDER BY  ";
    for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ )
    {
        if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" )
        {
            $sOrder .= $aColumns[ intval( $_GET['iSortCol_'.$i] ) ]."
                ".$db_con->quote( $_GET['sSortDir_'.$i] ) .", ";
        }
    }

    $sOrder = substr_replace( $sOrder, "", -2 );
    if ( $sOrder == "ORDER BY" )
    {
        $sOrder = "";
    }
}


/* 
 * Filtering
 * NOTE this does not match the built-in DataTables filtering which does it
 * word by word on any field. It's possible to do here, but concerned about efficiency
 * on very large tables, and MysqL's regex functionality is very limited
 */
$sWhere = "";
if ( $_GET['sSearch'] != "" )
{
    $sWhere = "WHERE (";
    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        $sWhere .= $aColumns[$i]." LIKE '%".$db_con->quote( $_GET['sSearch'] )."%' OR ";
    }
    $sWhere = substr_replace( $sWhere, "", -3 );
    $sWhere .= ')';
}

/* Individual column filtering */
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
    if ( $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' )
    {
        if ( $sWhere == "" )
        {
            $sWhere = "WHERE ";
        }
        else
        {
            $sWhere .= " AND ";
        }
        $sWhere .= $aColumns[$i]." LIKE '%".$db_con->quote($_GET['sSearch_'.$i])."%' ";
    }
}
$my = str_replace(" , ", " ", implode(", ", $aColumns));

/*
 * sql queries
 * Get data to display
 */
$sQuery = $db_con->query("SELECT {$my} FROM   {$sTable} {$sWhere} {$sOrder} {$sLimit}")->fetchAll(); 
//$rResult = ( $sQuery );

/* Data set length after filtering */
$sQuery = "
    SELECT FOUND_ROWS()
";
//$rResultFilterTotal = $sQuery;
$aResultFilterTotal = $sQuery;
$iFilteredTotal = $aResultFilterTotal[0];

/* Total data set length */
$sQuery = "
    SELECT COUNT(".$sIndexColumn.")
    FROM   $sTable
";
$rResultTotal = $db_con->query( $sQuery ) or die(MysqL_error());
$aResultTotal = $rResultTotal->fetchAll();
$iTotal = $aResultTotal[0];


/*
 * Output
 */
$output = array(
    "sEcho" => intval($_GET['sEcho']),
    "iTotalRecords" => $iTotal,
    "iTotaldisplayRecords" => $iFilteredTotal,
    "aaData" => array()
);

while ( $aRow = $rResult->fetchAll() )
{
    $row = array();
    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        if ( $aColumns[$i] == "version" )
        {
            /* Special output formatting for 'version' column */
            $row[] = ($aRow[ $aColumns[$i] ]=="0") ? '-' : $aRow[ $aColumns[$i] ];
        }
        else if ( $aColumns[$i] != ' ' )
        {
            /* General output */
            $row[] = $aRow[ $aColumns[$i] ];
        }
    }
    $output['aaData'][] = $row;
}

echo json_encode( $output );

错误：
但是我遇到了错误,我不知道上面要更改什么,请开始使用pdo,请使用代码更新答案：

更新了代码,现在收到以下错误

[28-Aug-2018 16:58:39 UTC] PHP Fatal error:  Uncaught exception 'PDOException' with message 'sqlSTATE[42000]: Syntax error or access violation: 1064 You have an error in your sql Syntax; check the manual that corresponds to your MysqL server version for the right Syntax to use near ''asc' LIMIT '0', '50'' at line 2' in C:\MAMP\htdocs\backend\my.PHP:131
Stack trace:
#0 C:\MAMP\htdocs\backend\my.PHP(131): PDO->query('SELECT first_na...')
#1 {main}
  thrown in C:\MAMP\htdocs\backend\my.PHP on line 131
**ERROR:**

解决方法:

我在这里看到一个问题：

$sWhere .= $aColumns[$i]." LIKE '%".$db_con->quote($_GET['sSearch_'.$i])."%' ";

PDO :: quote()函数的输出与旧的MysqL_real_escape_string()函数不同.

假设您的字符串是“ O’Reilly”,并且您需要转义撇号字符.

MysqL_real_escape_string(“ O’Reilly”)将返回：

    O\'Reilly

而$db_con-" quote(“ O’Reilly”)将返回：

    'O\'Reilly'

quote()函数将字符串定界符添加到字符串的开头和结尾.这使其与MysqL内置函数 QUOTE()相同

因此,当您使用PDO :: quote()的方式时：

$sWhere .= $aColumns[$i]." LIKE '%".$db_con->quote($_GET['sSearch_'.$i])."%' ";

产生的sql子句如下所示：

... WHERE mycolumn LIKE '%'search'%' ...

这是行不通的.您需要它是：

... WHERE mycolumn LIKE '%search%' ...

一种解决方案是添加％通配符,然后引用结果：

$sWhere .= $aColumns[$i]." LIKE ".$db_con->quote('%'.$_GET['sSearch_'.$i].'%') ;

现在,它利用PDO :: quote()添加字符串定界符.

顺便说一下,我找到了所有.字符串连接使PHP看起来很糟糕.很难编写代码,也很难阅读和调试代码.我更喜欢直接在字符串内部使用变量.并且不要害怕用两行代码来完成这项工作.对于代码可读性而言,将太多内容填入一行并不总是最好的.

$pattern = $db_con->quote("%{$_GET["sSearch_$i"]}%");

$sWhere .= "{$aColumns[$i]} LIKE {$pattern}";

但是还有另一种更容易,更安全的方式.

使用查询参数代替转义/引用.

$params[] = "%{$_GET["sSearch_$i"]}%";

$sWhere .= "{$aColumns[$i]} LIKE ?";

后来…

$stmt = $db_con->prepare($sQuery);
$stmt->execute($params);
while ($row = $stmt->fetchAll()) {
    ...
}

使用参数比使用转义/引用更简单.您不必费神去问报价是否正确平衡,因为参数占位符？不需要字符串定界符.

如果您正在学习PDO,建议您阅读以下内容：

> https://phpdelusions.net/pdo-一个很好的教程.
> http://php.net/pdo-参考文档.

两者都是重要和有用的.参考文档并不适合学习,但是在您学习本教程之后,它们对您有用,以提醒您自己语法,参数,返回值等.我已经做了很多PDO编码,但是我经常打开参考文档.

php-使用PDO查询代替mysql,即已弃用

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