如何使用 pdo 而不是大型数组从数据库获取可迭代结果集？
我在数据库抽象库函数 query< 中使用 PDO /code> 我做的。
我正在使用 fetchAll()，如果你有很多结果，应该会占用大量内存，所以我想提供一个参数来在 fetchAll 关联数组和 pdo 结果集之间切换，该结果集可以使用 foreach 进行迭代，并且需要更少的内存（以某种方式）。
我记得听说过这个，并且我搜索了 PDO 文档，但我找不到任何有用的方法来做到这一点。
有谁知道如何从 PDO 获取可迭代的结果集而不仅仅是平面数组？我认为使用可迭代的结果集会更容易占用内存，对吗？
我正在使用 Postgresql，如果在这种情况下很重要的话。
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。
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为了清楚起见，当前的查询函数如下。
/**
* Running bound queries on the database.
*
* Use: query('select all from players limit :count', array('count'=>10));
* Or: query('select all from players limit :count', array('count'=>array(10, PDO::PARAM_INT)));
**/
function query($sql_query, $bindings=array()){
DatabaseConnection::getInstance();
$statement = DatabaseConnection::$pdo->prepare($sql_query);
foreach($bindings as $binding => $value){
if(is_array($value)){
$statement->bindParam($binding, $value[0], $value[1]);
} else {
$statement->bindValue($binding, $value);
}
}
$statement->execute();
// TODO: Return an iterable resultset here, and allow switching between array and iterable resultset.
return $statement->fetchAll(PDO::FETCH_ASSOC);
}
I'm using PDO inside a database abstraction library function query that I've made.
I'm using fetchAll(), which if you have a lot of results, is supposed to get memory intensive, so I want to provide an argument to toggle between a fetchAll associative array and a pdo result set that can be iterated over with foreach and requires less memory (somehow).
I remember hearing about this, and I searched through the PDO docs, but I couldn't find any useful way to do that.
Does anyone know how to get an iterable resultset back from PDO instead of just a flat array? And am I right that using an iterable resultset will be easier on memory?
I'm using Postgresql, if it matters in this case.
.
.
.
The current query function is as follows, just for clarity.
/**
* Running bound queries on the database.
*
* Use: query('select all from players limit :count', array('count'=>10));
* Or: query('select all from players limit :count', array('count'=>array(10, PDO::PARAM_INT)));
**/
function query($sql_query, $bindings=array()){
DatabaseConnection::getInstance();
$statement = DatabaseConnection::$pdo->prepare($sql_query);
foreach($bindings as $binding => $value){
if(is_array($value)){
$statement->bindParam($binding, $value[0], $value[1]);
} else {
$statement->bindValue($binding, $value);
}
}
$statement->execute();
// TODO: Return an iterable resultset here, and allow switching between array and iterable resultset.
return $statement->fetchAll(PDO::FETCH_ASSOC);
}
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看起来我已经以 PDOStatement 对象本身的形式找到了解决方案，即在执行
$statement->execute();之后，您可以简单地传递$statement object 并 foreach 该对象。不能将它用作数组，但可以用它做几乎所有其他事情。Looks like I've found my solution in the form of the PDOStatement object itself, i.e. after doing a
$statement->execute();You can simply pass along the$statementobject and foreach over that object. Can't use it as an array, but can do just about everything else with it.