diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5cf6956..865bfb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,7 +25,7 @@ FIXED:
 
 - `WHERE` conditions won't be erased when using `SelectQueryBuilder::fetchById()`
 - Fetching relationships of an empty list of entities won't raise syntax error
-- Retrieving belongs-to relationships won't raise exception
+- Retrieval of belongs-to relationships
 
 ## 0.2.0 - 2017-02-17
 
diff --git a/src/Model/Relationship/AbstractRelationship.php b/src/Model/Relationship/AbstractRelationship.php
index 68ee59c..b9a86f0 100644
--- a/src/Model/Relationship/AbstractRelationship.php
+++ b/src/Model/Relationship/AbstractRelationship.php
@@ -50,14 +50,16 @@ public function cascadeDelete(Persister $persister, string $relationshipName, $p
         }
     }
 
-    protected function getWhereCondition(string $prefix, string $foreignKey, array $entities): ConditionBuilderInterface
-    {
+    protected function getWhereCondition(
+        array $entities,
+        string $entityKey,
+        string $prefix,
+        string $foreignKey
+    ): ConditionBuilderInterface {
         $values = [];
         foreach ($entities as $entity) {
-            $id = $this->parentModel->getId($entity);
-
-            if ($id !== null) {
-                $values[] = $id;
+            if (isset($entity[$entityKey])) {
+                $values[] = $entity[$entityKey];
             }
         }
 
diff --git a/src/Model/Relationship/BelongsToOneRelationship.php b/src/Model/Relationship/BelongsToOneRelationship.php
index a42418a..2822694 100644
--- a/src/Model/Relationship/BelongsToOneRelationship.php
+++ b/src/Model/Relationship/BelongsToOneRelationship.php
@@ -60,7 +60,14 @@ public function getQueryBuilder(array $entities): SelectQueryBuilderInterface
                         $this->relatedModel->getTable()
                     )
             )
-            ->where($this->getWhereCondition($this->relatedModel->getTable(), $this->referencedKey, $entities));
+            ->where(
+                $this->getWhereCondition(
+                    $entities,
+                    $this->foreignKey,
+                    $this->relatedModel->getTable(),
+                    $this->referencedKey
+                )
+            );
     }
 
     public function connectToParent(SelectQueryBuilderInterface $selectQueryBuilder)
diff --git a/src/Model/Relationship/HasManyThroughRelationship.php b/src/Model/Relationship/HasManyThroughRelationship.php
index 00faf14..90be44a 100644
--- a/src/Model/Relationship/HasManyThroughRelationship.php
+++ b/src/Model/Relationship/HasManyThroughRelationship.php
@@ -82,7 +82,14 @@ public function getQueryBuilder(array $entities): SelectQueryBuilderInterface
                         $this->relatedModel->getTable()
                     )
             )
-            ->where($this->getWhereCondition($this->junctionModel->getTable(), $this->foreignKey1, $entities));
+            ->where(
+                $this->getWhereCondition(
+                    $entities,
+                    $this->referencedKey1,
+                    $this->junctionModel->getTable(),
+                    $this->foreignKey1
+                )
+            );
     }
 
     public function connectToParent(SelectQueryBuilderInterface $selectQueryBuilder)
diff --git a/src/Model/Relationship/HasOneRelationship.php b/src/Model/Relationship/HasOneRelationship.php
index 3a60a5a..70353fb 100644
--- a/src/Model/Relationship/HasOneRelationship.php
+++ b/src/Model/Relationship/HasOneRelationship.php
@@ -49,7 +49,14 @@ public function getQueryBuilder(array $entities): SelectQueryBuilderInterface
         return SelectQueryBuilder::create()
             ->selectColumn("*")
             ->from($this->relatedModel->getTable())
-            ->where($this->getWhereCondition($this->relatedModel->getTable(), $this->foreignKey, $entities));
+            ->where(
+                $this->getWhereCondition(
+                    $entities,
+                    $this->referencedKey,
+                    $this->relatedModel->getTable(),
+                    $this->foreignKey
+                )
+            );
     }
 
     public function connectToParent(SelectQueryBuilderInterface $selectQueryBuilder)