Database relationships

Relationships between database

*** Entities can be linked between databases, this is called a relationship. ## Types of relationships - One to one - One to many - Many to many ## Relationship modeling Relationships can be modeled using an entity relationship diagram. ## Relational databases There are a few concepts with a relational database. ### Foreign key A foreign key is a attribute that has been linked to an external table. The foreign key is the primary key an another database. ![[Foreign key.png|500]]