From b1fcdf94e92adfb5177f0f1bc0a2444bfbefc562 Mon Sep 17 00:00:00 2001
From: Kazantcev Andrey <45011689+heckad@users.noreply.github.com>
Date: Mon, 17 Jun 2019 00:15:28 +0300
Subject: [PATCH] Fix
 https://github.com/marshmallow-code/flask-marshmallow/issues/44

---
 src/marshmallow_sqlalchemy/schema.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/marshmallow_sqlalchemy/schema.py b/src/marshmallow_sqlalchemy/schema.py
index f347da00..a4ff5246 100644
--- a/src/marshmallow_sqlalchemy/schema.py
+++ b/src/marshmallow_sqlalchemy/schema.py
@@ -173,7 +173,7 @@ def get_instance(self, data):
 
         :param data: Serialized data to inform lookup.
         """
-        if self.transient:
+        if self.transient or not hasattr(self.session, 'query'):
             return None
         props = get_primary_keys(self.opts.model)
         filters = {prop.key: data.get(prop.key) for prop in props}