notes/School/Development/Foreign Key.md

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).

Example

Authors

ID (PK)	Name	Age	Sex	Length
1	Nick	21	M	190
Authors
ID (PK)	Job	Age	Sex	Length
-----	-----	-----	-----	-----
1	Nick	21	M	190