如何使用mongodb和php正确处理分页查询? [英] How to handle pagination queries properly with mongodb and php?

问题描述

我这样做正确吗?我查看了一些带有MySQL的旧PHP代码，并设法使其正常工作，但是我想知道是否存在实现此目标的更干净"和更快"的方法.

首先，我需要获取文档"的总数

$total_documents = $collection->find(array("tags" => $tag, 
        "seeking" => $this->session->userdata('gender'), 
        "gender" => $this->session->userdata('seeking')))->count();

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;
$total_pages = ceil($total_documents / $limit);

//查询以填充数组，以便可以分页显示

$data['result'] = $collection->find(array("tags" => $tag, 
        "seeking" => $this->session->userdata('gender'), 
        "gender" => $this->session->userdata('seeking')))->limit($limit)->skip($skip)->sort(array("_id" => -1));

我的问题是，我可以一次运行查询吗?我基本上运行两次相同的查询，除了第二次我传递值以在记录之间跳过.

-新代码...

好吧，除非有人知道另一种方式(如果可能)，我要说这是不可行的.话虽如此，我改变了通过mongodb运行查询的方式，这产生了更好的代码. ;-)我试图尽量减少访问DB的次数，但是希望这不会对性能造成影响.我的另一尝试是计算数组中元素的数量，但很快发现，由于$ limit& $ skip参数将提供ITS的文档总数.

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;

$query = array("loc" => array('$near' => array('lat' => $latitude, 'lon' => $longitute) ),
        "tags" => $tag, "seeking" => $this->session->userdata('gender'),
        "gender" => $this->session->userdata('seeking'));

$fields = array("username", "zipcode", "tags", "birth_date");
$total_documents = $collection->find($query, array("_id"))->count();
$data['result'] = $collection->find($query, $fields)->limit($limit)->skip($skip);

解决方案

由于find()-> limit()-> skip()的结果是Mongo_Cursor，因此您不必执行两次实际查询. /p>

以下内容也应工作:

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;

$query = array("loc" => array('$near' => array('lat' => $latitude, 'lon' => $longitute) ),
    "tags" => $tag, "seeking" => $this->session->userdata('gender'),
    "gender" => $this->session->userdata('seeking'));

$fields = array("username", "zipcode", "tags", "birth_date");
$cursor = $collection->find($query, $fields)->limit($limit)->skip($skip);
$total_documents = $cursor->count();
$data['result'] = $cursor;

顺便说一句，我首先误解了您的问题，我以为您对限制&跳过.

Am I doing this right? I went to look at some old PHP code w/ MySQL and I've managed to get it to work, however I'm wondering if there's a much "cleaner" and "faster" way of accomplishing this.

First I would need to get the total number of "documents"

$total_documents = $collection->find(array("tags" => $tag, 
        "seeking" => $this->session->userdata('gender'), 
        "gender" => $this->session->userdata('seeking')))->count();

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;
$total_pages = ceil($total_documents / $limit);

// Query to populate array so I can display with pagination

$data['result'] = $collection->find(array("tags" => $tag, 
        "seeking" => $this->session->userdata('gender'), 
        "gender" => $this->session->userdata('seeking')))->limit($limit)->skip($skip)->sort(array("_id" => -1));

My question is, can I run the query in one shot? I'm basically running the same query twice, except the second time I'm passing the value to skip between records.

-- New code ...

Ok, unless someone knows of another way to do this (if it's possible), I'm going to say it's not doable. With that said, I changed the way I run my queries through mongodb, which yielded better looking code. ;-) I was trying to minimize the trips to the DB, but oh well hopefully this doesn't take a performance hit. My other attempt was to count the number of elements in the array, but quickly found out that wouldn't work since the $limit & $skip parameters would give ITS total number of docs.

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;

$query = array("loc" => array('$near' => array('lat' => $latitude, 'lon' => $longitute) ),
        "tags" => $tag, "seeking" => $this->session->userdata('gender'),
        "gender" => $this->session->userdata('seeking'));

$fields = array("username", "zipcode", "tags", "birth_date");
$total_documents = $collection->find($query, array("_id"))->count();
$data['result'] = $collection->find($query, $fields)->limit($limit)->skip($skip);

解决方案

Since the result of find()->limit()->skip() is a Mongo_Cursor you don't have to execute the actual query twice.

The following should work as well :

$skip = (int)($docs_per_page * ($page - 1));
$limit = $docs_per_page;

$query = array("loc" => array('$near' => array('lat' => $latitude, 'lon' => $longitute) ),
    "tags" => $tag, "seeking" => $this->session->userdata('gender'),
    "gender" => $this->session->userdata('seeking'));

$fields = array("username", "zipcode", "tags", "birth_date");
$cursor = $collection->find($query, $fields)->limit($limit)->skip($skip);
$total_documents = $cursor->count();
$data['result'] = $cursor;

btw I first misread your question, I thought you didn't know about limit & skip.

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