我对PDO声明有问题＆＃34;更新＆＃34;。我想使用以下代码更新数据库中的现有列：
<?php
$sql="UPDATE $title SET header = $header;";
for($co=1,$arr=0;$co<=$count;$co++,$arr++)
{
$sql .= "UPDATE $title SET theme$co = :theme, content$co = :content;";
$insert = array('theme' => $theme[$arr], 'content' => $content[$arr]);
$statement = $pdo->prepare($sql);
$statement->execute($insert);
}
?>
问题是，当完成此代码时，数据库中没有任何事情发生。 阵列＆＃34;主题＆＃34; ＆安培; ＆＃34;内容＆＃34;只包含一些用户已写入其中的文本。根据用户输入的主题/内容的数量，您获得的阵列越多。例如：
$theme1="a";
$theme2="b";
$content1="abc";
$content2="def";
因此在数据库中，已经创建了与主题相同名称的列。内容数组。现在我想要做的是，将例如$ theme1的值插入到列＃34; theme1＆＃34;与$ content1相同的事情＆＃34; content1＆＃34;等等...
我已经尝试过更改
$sql .= to $sql =
并将其作为单个查询执行。但那也没有用。
我没有使用＆＃34; Insert＆＃34;声明，因为它总是在数据库中创建一个新行，所以它看起来像this 正如您在屏幕截图中看到的那样，这是完全错误的，我试图将所有内容都放在一行中。这就是我尝试更新而不是插入的原因。 由于表格及其所有列的创建与PDO一起工作正常，我想知道为什么Update根本不起作用。
编辑：变量＆＃34; titel＆＃34;没有拼错，我是德国人，这对我来说是对的。由于您可以根据需要命名变量，因此我可以用母语进行操作。但是，无论如何，谢谢告诉我，我试图用英语单词替换所有德语变量，但我错过了那个，所以我现在改变了。
答案 0 :(得分：0)
这是我的解决方案。它包含错误报告/显示以及将PDO预处理语句与exception handling结合使用所涉及的所有适当步骤。
代码已注释。
尝试使用sprintf function来适应自己。有了它，您可以以优雅的方式构建非常复杂的sql语句。
祝你好运！<?php
/*
* ============================================================
* Set error reporting level and display errors on screen.
* Use it ONLY ON A DEVELOPMENT SYSTEM, NEVER ON PRODUCTION!
* If you activate it on a live system, then the users will see
* all the errors of your system. And you don't want this!
* ============================================================
*/
error_reporting(E_ALL);
ini_set('display_errors', 1);
/*
* User variables.
*/
// "table name" not "title" ;-)
$tableName = 'your_table';
// "Themes" not "theme" ;-)
$themes = array('t1', 't2', 't3', 't4', 't5');
// "Contents" not "content" ;-)
$contents = array('c1', 'c2', 'c3', 'c4', 'c5');
// Counter for building the sql statement's assignment list
// and the input parameters list for the sql statement's markers.
$count = 5;
try {
/*
* Create a PDO instance as db connection to a MySQL db.
*/
$connection = new PDO(
'mysql:host=localhost;port=3306;dbname=yourDb;charset=utf8'
, 'yourDbUsername'
, 'yourDbPassword'
);
/*
* Assign the driver options to the db connection.
*/
$connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, FALSE);
$connection->setAttribute(PDO::ATTR_PERSISTENT, TRUE);
/*
* Build the sql statement and fill the input parameters list.
*
* ------------------------------------------------------------------------
* Notes:
*
* - Quote: "You cannot use a named parameter marker of the same name more
* than once in a prepared statement, unless emulation mode is on."
* See: http://php.net/manual/de/pdo.prepare.php
*
* - DON'T use semicolon at the end of sql statements in PHP!
* ------------------------------------------------------------------------
*/
// Sql statement's assignment list. Array of "column-name = :column-marker, ..." assignments.
$assignments = array();
// Input parameters list, e.g the values for the sql statement markers.
$bindings = array();
// Note: Use one iteration variable for both operations!
for ($i = 1; $i <= $count; $i++) {
// Add sql assignments to assignment list.
$assignments[] = sprintf('theme%s = :theme%s, content%s = :content%s', $i, $i, $i, $i);
// Add corresponding input parameter values to bindings list.
$bindings[':theme' . $i] = $themes[$i - 1];
$bindings[':content' . $i] = $contents[$i - 1];
}
// Final sql statement.
$sql = sprintf(
'UPDATE %s
SET header = %s
%s'
, $tableName
, $header
, $assignments ? ',' . implode(',', $assignments) : ''
);
/*
* Prepare and validate the sql statement.
*
* --------------------------------------------------------------------------------
* If the database server cannot successfully prepare the statement, PDO::prepare()
* returns FALSE or emits PDOException (depending on error handling settings).
* --------------------------------------------------------------------------------
*/
$statement = $connection->prepare($sql);
if (!$statement) {
throw new UnexpectedValueException('The sql statement could not be prepared!');
}
/*
* Bind the input parameters to the prepared statement.
*
* -----------------------------------------------------------------------------------
* Unlike PDOStatement::bindValue(), when using PDOStatement::bindParam() the variable
* is bound as a reference and will only be evaluated at the time that
* PDOStatement::execute() is called.
* -----------------------------------------------------------------------------------
*/
foreach ($bindings as $key => $value) {
// Get the name of the input parameter by its key in the bindings array.
$inputParameterName = is_int($key) ? ($key + 1) : (':' . ltrim($key, ':'));
// Get the PDO::PARAM_* constant, e.g the data type of the input parameter, by its value.
$inputParameterDataType = PDO::PARAM_STR;
if (is_int($value)) {
$inputParameterDataType = PDO::PARAM_INT;
} elseif (is_bool($value)) {
$inputParameterDataType = PDO::PARAM_BOOL;
}
// Bind the input parameter.
$bound = $statement->bindValue($inputParameterName, $value, $inputParameterDataType);
if (!$bound) {
throw new UnexpectedValueException('An input parameter can not be bound!');
}
}
/*
* Execute the prepared statement.
*
* ------------------------------------------------------------------
* PDOStatement::execute returns TRUE on success or FALSE on failure.
* ------------------------------------------------------------------
*/
$executed = $statement->execute();
if (!$executed) {
throw new UnexpectedValueException('The prepared statement can not be executed!');
}
/*
* Get number of affected rows.
*/
$numberOfAffectedRows = $statement->rowCount();
/*
* Display results.
*/
echo $numberOfAffectedRows;
/*
* Close connection.
*/
$connection = NULL;
} catch (PDOException $exc) {
echo $exc->getMessage();
// Log the whole exception object to a file.
// $logger->log($exc);
exit();
} catch (Exception $exc) {
echo $exc->getMessage();
// Log the whole exception object to a file.
// $logger->log($exc);
exit();
}
如果您愿意，请参阅我的答案here（＆＃34;编辑＆＃34;部分），我在其中发布了数据库适配器类。它负责处理所有数据库操作，验证和异常处理案例。