mongodb中随机获取1条记录的实现方法

<?php// 连接mongodbfunction conn($host, $user, $passwd){ $server = 'mongodb://'.$user.':'.$passwd.'@'.$host; try{  $conn = new MongoDB/Driver/Manager(); } catch (MongoDB/Driver/Exception/ConnectionException $e){  throw new ErrorException('Unable to connect to db server. Error:' . $e->getMessage(), 31); } return $conn;}// 插入数据function add($conn, $dbname, $collname, $data, $index){ // 创建索引 $cmd = array(  'createIndexes' => $collname,  'indexes' => array(   array(    'name' => 'index',    'key' => $index,    'ns' => $dbname.'.'.$collname   )  ) ); $command = new MongoDB/Driver/Command($cmd); $conn->executeCommand($dbname, $command); // 插入数据 $bulk = new MongoDB/Driver/BulkWrite(); $inserted = 0; if($data){  foreach($data as $k=>$v){   $bulk->insert($v);  }  $result = $conn->executeBulkWrite($dbname.'.'.$collname, $bulk);  $inserted = $result->getInsertedCount(); } return $inserted;}// 获取总记录数function getCount($conn, $dbname, $collname){ $cmd = array(  'count' => $collname,  'query' => array() ); $command = new MongoDB/Driver/Command($cmd); $result = $conn->executeCommand($dbname, $command); $response = current($result->toArray()); if($response->ok==1){  return $response->n; } return 0;}// 随机获取一条记录function randOne($conn, $dbname, $collname){ // 总记录数 $total = getCount($conn, $dbname, $collname); // 随机偏移 $skip = mt_rand(0, $total-1); $filter = array(); $options = array('skip'=>$skip, 'limit'=>1); $query = new MongoDB/Driver/Query($filter, $options); $cursor = $conn->executeQuery($dbname.'.'.$collname, $query); $result = array(); if($cursor){  foreach($cursor as $v){   $v = objectToArray($v);   unset($v['_id']);   $result[] = $v;  } } return $result? $result[0] : $result;}// 对象转为数组function objectToArray($obj){ $arr = is_object($obj) ? get_object_vars($obj) : $obj; if(is_array($arr)){  return array_map(__FUNCTION__, $arr); }else{  return $arr; }}?>

<?phprequire('function.php');// 连接mongodb$conn = conn('localhost','testdb','root','123456');// 插入50条数据记录$data = array();// 索引$index = array('user'=>true);for($i=0; $i<50; $i++){ $data[] = array(  'user' => 'test_user_'.str_pad($i, 4, '0', STR_PAD_LEFT) );}$inserted = add($conn, 'testdb', 'user', $data, $index);echo '成功插入'.$inserted.'条测试记录数<br><br>';// 随机获取一条记录,抽5次echo '随机获取一条记录，抽5次<br>';$result = array();for($i=0; $i<5; $i++){ $result[] = randOne($conn, 'testdb', 'user');}echo '<pre>';print_r($result);echo '</pre>';?>

Array( [0] => Array  (   [user] => test_user_0017  ) [1] => Array  (   [user] => test_user_0026  ) [2] => Array  (   [user] => test_user_0004  ) [3] => Array  (   [user] => test_user_0043  ) [4] => Array  (   [user] => test_user_0023  ))

use testdbdb.createUser(  {   "user":"root",   "pwd":"123456",   "roles":[{"role" : "readWrite", "db":"testdb"}]  } ) db.auth(  {   "user":"root",   "pwd":"123456"  } )