diff --git a/Database-Schema.md b/Database-Schema.md
index 9c283ef..c58a6e1 100644
--- a/Database-Schema.md
+++ b/Database-Schema.md
@@ -43,11 +43,13 @@ SHOW TABLES IN Plan;
 
 [![Database Schema](https://raw.githubusercontent.com/plan-player-analytics/drawio-diagrams-storage/master/Database%20Schema.drawio.svg)](https://app.diagrams.net/#Hplan-player-analytics%2Fdrawio-diagrams-storage%2Fmaster%2FDatabase%20Schema.drawio.svg)
 
-## Data types
-
 ### Notes
 
-`plan_servers.uuid`: This uuid is ServerUUID, which the server generates the first time the server connects to the database. It can be found in ServerInfoFile.yml inside Plan plugin folder.
+- `plan_servers.uuid`: This uuid is ServerUUID, which the server generates the first time the server connects to the database. It can be found in ServerInfoFile.yml inside Plan plugin folder.
+- `server_uuid` columns refer to `plan_servers.uuid` without a foreign key.
+- `uuid`, `killer_uuid` & `victim_uuid` columns refer to `plan_users.uuid` without a foreign key.
+
+## Data types
 
 ```sql
 SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH, COLUMN_DEFAULT FROM information_schema.columns WHERE table_schema = 'Plan';