Merge 7605464 into c55d42d

.gitignore

@@ -8,3 +8,4 @@ composer.lock
 *.project
 .idea/
 .phpunit.result.cache
+.vscode

src/Jenssegers/Mongodb/Query/Builder.php

@@ -844,6 +844,10 @@ protected function performUpdate($query, array $options = [])
      */
     public function convertKey($id)
     {
+        if (is_array($id)) {
+            return array_map(array($this, __FUNCTION__), $id);
+        }
+
         if (is_string($id) && strlen($id) === 24 && ctype_xdigit($id)) {
             return new ObjectID($id);
         }

src/Jenssegers/Mongodb/Relations/BelongsTo.php

@@ -21,12 +21,21 @@ public function getHasCompareKey()
      */
     public function addConstraints()
     {
-        if (static::$constraints) {
-            // For belongs to relationships, which are essentially the inverse of has one
-            // or has many relationships, we need to actually query on the primary key
-            // of the related models matching on the foreign key that's on a parent.
-            $this->query->where($this->getOwnerKey(), '=', $this->parent->{$this->foreignKey});
+        if (!static::$constraints) {
+            return;
         }
+        // For belongs to relationships, which are essentially the inverse of has one
+        // or has many relationships, we need to actually query on the primary key
+        // of the related models matching on the foreign key that's on a parent.
+        $foreign = $this->parent->{$this->foreignKey};
+        // Check if the foreign key is an array, so we can infer the cardinality of the relationship.
+        if (is_array($foreign)) {
+            // This means that it is a one-to-many relationship. Try a match using whereIn.
+            $this->query->whereIn($this->getOwnerKey(), $foreign);
+            return;
+        }
+        // It's a one-to-one relationship, just match using the classic equals operator.
+        $this->query->where($this->getOwnerKey(), '=', $foreign);
     }
 
     /**