mongodbphpautoincrement自增

> db.counters.insert( //计数器表
 {
 _id: "userid",
 seq: 0
 }
 );
WriteResult({ "nInserted" : 1 })
> db.counters.find();
{ "_id" : "userid", "seq" : 0 }
> function getNextSequence(name) { //取下个ID的函数
 var ret = db.counters.findAndModify(
 {
 query: { _id: name },
 update: { $inc: { seq: 1 } }, //这里seq就是上面counters表中的seq字段
 new: true,
 upsert: true
 }
 );
 return ret.seq;
 };
> db.users.insert( //插入数据
 {
 _id: getNextSequence("userid"),
 name: "tank"
 }
 );
WriteResult({ "nInserted" : 1 })
> db.users.find(); //查看
{ "_id" : 1, "name" : "tank" }
> db.users.insert(
 {
 _id: getNextSequence("userid"),
 name: "test"
 }
 );
WriteResult({ "nInserted" : 1 })
> db.users.find();
{ "_id" : 1, "name" : "tank" }
{ "_id" : 2, "name" : "test" }

function getNextId($mongo,$name,$param=array()){
 $param += array( //默认ID从1开始,间隔是1
 'init' => 1,
 'step' => 1,
 );
 $update = array('$inc'=>array('id'=>$param['step'])); //设置间隔
 $query = array('name'=>$name);
 $command = array(
 'findandmodify' => 'ids',
 'update' => $update,
 'query' => $query,
 'new' => true
 );
 $id = $mongo->db->command($command);
 if (isset($id['value']['id'])) {
 return $id['value']['id'];
 }else{
 $mongo->insert(array(
 'name' => $name,
 'id' => $param['init'], //设置ID起始数值
 ));
 return $param['init'];
 }
} 
$mongo = new Mongo();
$curDB = $mongo->selectCollection('test', 'ids'); //test库中的ids表
$user = $mongo->selectCollection('test', 'users'); //test库中的users表
$id = getNextId($curDB,'userid',array('init'=>10000,'step'=>2)); //取得下一条数据的ID
$obj = array("_id"=>$id,"name"=>"tankzhang");
$user->insert($obj); //插入数据