Vault sync: 2021-10-25 17:11:26

School/Development/Foreign Key.md

@@ -1,6 +1,8 @@
 # Foreign Key
 A Foreign key is a [[Constraint]] that protects links between tables. Foreign key is a attribute or attributes that link to the [[Primary Key]] of a other entity set (table).
 
-For 
-
+## Example
 
+|ID (PK)|Name|Age|Sex|Length|
+|-----|-----|-----|-----|-----|
+|1|Nick|21|M|190|

School/Development/Primary Key.md

@@ -5,4 +5,8 @@ There can only be ONE primary per table and can consist of multiple attributes (
 
 A primary key is **not** required, but highly advised. Even if you don't use it its better to include one in your schema.
 
-## Exaple
+## Example
+
+**Name (PK) - Age - Sex - Length**
+
+In the table schema above, only one entity where the name is Nick can exist because Name is the primary key.