PHP MongoDB How to return the current insert record ID after inserting data

<?php
/**
* Insert Record
* Parameters:
* $table _name: Table name
* $record: Record
*
* return value:
* Success: True
* Failed: false
*
/function Insert ($table _name, $record) {
	$dbname = $this->curr_db_name;
	try{
		$this->mongo-> $dbname->insert ($record, Array (' safe ' =>true); The method to perform a secure write is return
		true;
	} catch (Mongocursorexception $e) {
		$this->error = $e->getmessage ();
		return false;
	}

? >

As shown in the figure:

The parameter $record is actually a pointer reference that automatically returns the _ID key in the $record array after the insert succeeds

Array ([
	0]=>array [
		username]=>username570
		[password]=>password200
	] [
	1]= > Insert before
)

Array ([
	0]=>array [
		username]=>username570
		[password]=>password200
		[_id]=>mongoid Object (
			[$id]=>35jdfas8dfsafaa9869
		)
	]
	[1]=>999
)

Note also that the returned $record ["_id"] is a Mongoid object that can be used directly as a MongoDB query condition and not converted back and forth.