Removed whereNull protection, fixes #97

src/Jenssegers/Mongodb/Query/Builder.php

@@ -402,9 +402,6 @@ class Builder extends \Illuminate\Database\Query\Builder {
             $query['$set'] = $extra;
         }
 
-        // Protect
-        $this->whereNotNull($column);
-
         return $this->performUpdate($query);
     }
 

tests/QueryBuilderTest.php

@@ -511,7 +511,6 @@ class QueryBuilderTest extends PHPUnit_Framework_TestCase {
 		DB::collection('users')->insert(array(
 			array('name' => 'John Doe', 'age' => 30, 'note' => 'adult'),
 			array('name' => 'Jane Doe', 'age' => 10, 'note' => 'minor'),
-			array('name' => 'Robert Roe', 'age' => null),
 			array('name' => 'Mark Moe'),
 		));
 
@@ -549,10 +548,8 @@ class QueryBuilderTest extends PHPUnit_Framework_TestCase {
 		$this->assertEquals(11, $user['age']);
 		$user = DB::collection('users')->where('name', 'Jane Doe')->first();
 		$this->assertEquals(21, $user['age']);
-		$user = DB::collection('users')->where('name', 'Robert Roe')->first();
-		$this->assertEquals(null, $user['age']);
 		$user = DB::collection('users')->where('name', 'Mark Moe')->first();
-		$this->assertFalse(isset($user['age']));
+		$this->assertEquals(1, $user['age']);
 	}
 
 }