如何使用pdo而不是大型数组从数据库中获取可迭代结果集？

Question

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.

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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); 
}

Answer 1

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 $statement object and foreach over that object. Can't use it as an array, but can do just about everything else with it.