diff --git a/.gitignore b/.gitignore
index 45505cc9..72733326 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ documents
 coverage.txt
 _book
 .idea
-vendor
\ No newline at end of file
+vendor
+.vscode
diff --git a/callbacks/associations.go b/callbacks/associations.go
index 4a50e6c2..00e00fcc 100644
--- a/callbacks/associations.go
+++ b/callbacks/associations.go
@@ -206,7 +206,7 @@ func SaveAfterAssociations(create bool) func(db *gorm.DB) {
 								}
 							}
 
-							cacheKey := utils.ToStringKey(relPrimaryValues)
+							cacheKey := utils.ToStringKey(relPrimaryValues...)
 							if len(relPrimaryValues) != len(rel.FieldSchema.PrimaryFields) || !identityMap[cacheKey] {
 								identityMap[cacheKey] = true
 								if isPtr {
@@ -292,7 +292,7 @@ func SaveAfterAssociations(create bool) func(db *gorm.DB) {
 								}
 							}
 
-							cacheKey := utils.ToStringKey(relPrimaryValues)
+							cacheKey := utils.ToStringKey(relPrimaryValues...)
 							if len(relPrimaryValues) != len(rel.FieldSchema.PrimaryFields) || !identityMap[cacheKey] {
 								identityMap[cacheKey] = true
 								distinctElems = reflect.Append(distinctElems, elem)
diff --git a/utils/utils_test.go b/utils/utils_test.go
index 5737c511..27dfee16 100644
--- a/utils/utils_test.go
+++ b/utils/utils_test.go
@@ -12,3 +12,20 @@ func TestIsValidDBNameChar(t *testing.T) {
 		}
 	}
 }
+
+func TestToStringKey(t *testing.T) {
+	cases := []struct {
+		values []interface{}
+		key    string
+	}{
+		{[]interface{}{"a"}, "a"},
+		{[]interface{}{1, 2, 3}, "1_2_3"},
+		{[]interface{}{[]interface{}{1, 2, 3}}, "[1 2 3]"},
+		{[]interface{}{[]interface{}{"1", "2", "3"}}, "[1 2 3]"},
+	}
+	for _, c := range cases {
+		if key := ToStringKey(c.values...); key != c.key {
+			t.Errorf("%v: expected %v, got %v", c.values, c.key, key)
+		}
+	}
+}