First start the mongod server;
Open a shell client:

use haha
db.haha.insert({‘a’:’aaa’})
db.haha.find()
{‘a’:’aaa’}//The addition was successful

Open another shell client:

use haha
Db.haha.find() // confirm the input just now
{‘a’:’aaa’}//It worked

As you can see, the shell client inside is effective.
The following is php code:

$m = new MongoClient();
$jihe = $m->db->haha;

$cursor = $jihe->find();
foreach($cursor as $item){
var_dump($item); //nothing, empty data
bracket

Then modify the php code to read:

$m = new MongoClient();
$jihe = $m->db->haha;

$doc = array(‘b’=>’bbb’);
$jihe->insert($doc);// php tries to insert data itself

$cursor = $jihe->find();
foreach($cursor as $item){
var_dump($item); //This time only{‘b’:’bbb’}Data, no shell set inside{‘a’:’aaa’}
bracket

What is going on here? It’s all for the same database. How is there such a difference between shell client and php access?