diff --git a/.obsidian/workspace b/.obsidian/workspace
index ccf6c8d..f505214 100644
--- a/.obsidian/workspace
+++ b/.obsidian/workspace
@@ -88,6 +88,7 @@
   "active": "bc6e8ad9aa0f44c3",
   "lastOpenFiles": [
     "School/Development/Primary Key.md",
+    "School/Development/Foreign Key.md",
     "School/Development/SQL Database.md",
     "School/Analyse/OSI Model.md",
     "School/Analyse/Images/OSI-model.png",
@@ -95,7 +96,6 @@
     "School/Analyse/Computer Networks.md",
     "School/Analyse/Comminucation Mediums.md",
     "School/Analyse/Network Types.md",
-    "School/Analyse/Network Hardware.md",
-    "School/Analyse/Packet.md"
+    "School/Analyse/Network Hardware.md"
   ]
 }
\ No newline at end of file
diff --git a/School/Development/Foreign Key.md b/School/Development/Foreign Key.md
new file mode 100644
index 0000000..15152ff
--- /dev/null
+++ b/School/Development/Foreign Key.md	
@@ -0,0 +1,4 @@
+# Foreign Key
+A Foreign key is a [[Constraint]] that protects links between tables.
+
+
diff --git a/School/Development/Primary Key.md b/School/Development/Primary Key.md
index 0d8f90c..b2c38d0 100644
--- a/School/Development/Primary Key.md	
+++ b/School/Development/Primary Key.md	
@@ -3,9 +3,6 @@ A Primary key is a [[Constraint]] that uniquely identifies [[SQL Database#Entity
 
 There can only be ONE primary per table and can consist of multiple attributes (columns).
 
-A primary key is **not** required, but highly advised. Even if you don't use it its better to include one in your scheme.
+There als o
 
-
-
-
- 
+A primary key is **not** required, but highly advised. Even if you don't use it its better to include one in your schema.
\ No newline at end of file