diff --git a/src/oidcop/session/database.py b/src/oidcop/session/database.py
index 47171d3e..bf75991b 100644
--- a/src/oidcop/session/database.py
+++ b/src/oidcop/session/database.py
@@ -126,46 +126,46 @@ def get(self, path: List[str]) -> Union[SessionInfo, Grant]:
 
     def delete(self, path: List[str]):
         uid, client_id, grant_id = self._eval_path(path)
-        try:
-            _user_info = self.db[uid]
-        except KeyError:
-            pass
-        else:
-            if client_id:
-                if client_id in _user_info.subordinate:
-                    try:
-                        _client_info = self.db[self.session_key(uid, client_id)]
-                    except KeyError:
-                        pass
-                    else:
-                        if grant_id:
-                            if grant_id in _client_info.subordinate:
-                                try:
-                                    self.db.__delitem__(
-                                        self.session_key(uid, client_id, grant_id))
-                                except KeyError:
-                                    pass
-                                _client_info.subordinate.remove(grant_id)
-                        else:
-                            for grant_id in _client_info.subordinate:
-                                self.db.__delitem__(
-                                    self.session_key(uid, client_id, grant_id))
-                            _client_info.subordinate = []
-
-                        if len(_client_info.subordinate) == 0:
-                            self.db.__delitem__(self.session_key(uid, client_id))
-                            _user_info.subordinate.remove(client_id)
-                        else:
-                            self.db[client_id] = _client_info
-
-                    if len(_user_info.subordinate) == 0:
-                        self.db.__delitem__(uid)
-                    else:
-                        self.db[uid] = _user_info
-                else:
-                    pass
+
+        if uid not in self.db:
+            return
+        elif not client_id:
+            self.db.__delitem__(uid)
+            return
+
+        _user_info = self.db[uid]
+        skey_uid_client = self.session_key(uid, client_id)
+        skey_uid_client_grant = self.session_key(
+            uid, client_id, grant_id or ''
+        )
+
+        if client_id not in _user_info.subordinate:
+            self.db.__delitem__(client_id)
+            return
+
+        elif skey_uid_client in self.db:
+            _client_info = self.db[skey_uid_client]
+            if grant_id:
+                if skey_uid_client_grant in self.db:
+                    self.db.__delitem__(skey_uid_client_grant)
+                if grant_id in _client_info.subordinate:
+                    _client_info.subordinate.remove(grant_id)
             else:
-                self.db.__delitem__(uid)
+                for grant_id in _client_info.subordinate:
+                    if skey_uid_client_grant in self.db:
+                        self.db.__delitem__(skey_uid_client_grant)
+                _client_info.subordinate = []
+
+            if len(_client_info.subordinate) == 0:
+                self.db.__delitem__(skey_uid_client)
+                _user_info.subordinate.remove(client_id)
+            else:
+                self.db[client_id] = _client_info
+
+        if len(_user_info.subordinate) == 0:
+            self.db.__delitem__(uid)
+        else:
+            self.db[uid] = _user_info
 
     def update(self, path: List[str], new_info: dict):
         _info = self.get(path)