Fixed issue mongodb#8

Author: mnphpexpert

Diff for: src/Jenssegers/Mongodb/Builder.php

@@ -268,8 +268,13 @@ public function insertGetId(array $values, $sequence = null)
 
         if (1 == (int) $result['ok'])
         {
+            if (!$sequence)
+            {
+                $sequence = '_id';
+            }
+
             // Return id as a string
-            return (string) $values['_id'];
+            return (string) $values[$sequence];
         }
     }
 

Diff for: tests/ModelTest.php

@@ -2,6 +2,7 @@
 require_once('vendor/autoload.php');
 require_once('models/User.php');
 require_once('models/Soft.php');
+require_once('models/Book.php');
 
 use Jenssegers\Mongodb\Connection;
 use Jenssegers\Mongodb\Model;
@@ -19,6 +20,7 @@ public function tearDown()
 	{
 		User::truncate();
 		Soft::truncate();
+		Book::truncate();
 	}
 
 	public function testNewModel()
@@ -204,4 +206,24 @@ public function testSoftDelete()
 		$this->assertEquals(1, $all->count());
 	}
 
+	public function testPrimaryKey()
+	{
+		$user = new User;
+		$this->assertEquals('_id', $user->getKeyName());
+
+		$book = new Book;
+		$this->assertEquals('title', $book->getKeyName());
+
+		$book->title = "A Game of Thrones";
+		$book->author = "George R. R. Martin";
+		$book->save();
+
+		$this->assertEquals("A Game of Thrones", $book->getKey());
+
+		$check = Book::find("A Game of Thrones");
+		$this->assertEquals('title', $check->getKeyName());
+		$this->assertEquals("A Game of Thrones", $check->getKey());
+		$this->assertEquals("A Game of Thrones", $check->title);
+	}
+
 }

Diff for: tests/models/Book.php

@@ -0,0 +1,12 @@
+<?php
+
+use Jenssegers\Mongodb\Model as Eloquent;
+
+class Book extends Eloquent {
+
+	protected $collection = 'books';
+
+	protected static $unguarded = true;
+
+	protected $primaryKey = 'title';
+}