Merge branch '3.0.x'

Author: davidism

CHANGES.rst

@@ -12,6 +12,9 @@ Version 3.0.3
 
 Unreleased
 
+-   Show helpful errors when mistakenly using multiple ``SQLAlchemy`` instances for the
+    same app, or without calling ``init_app``. :pr:`1151`
+
 
 Version 3.0.2
 -------------

docs/queries.rst

@@ -51,7 +51,7 @@ returned rows.
 
 .. code-block:: python
 
-    user = db.session.execute(db.select(User).filter_by(username=username)).one()
+    user = db.session.execute(db.select(User).filter_by(username=username)).scalar_one()
 
     users = db.session.execute(db.select(User).order_by(User.username)).scalars()