mongodb 随机获取一条记录的方法

<?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>';?>

成功插入50条测试记录数随机获取一条记录，抽5次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    ))

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