Database Relationships: Many-to-Many and One-to-One

Show Notes available via: http://howtoprogramwithjava.com/session43

 

In this post we will be expanding on the topic of database relationships and touch on two that are less common but just as useful.

Many-to-Many Relationship

The many-to-many database relationship is used when you are in the situation where the rows in the first table can map to multiple rows in the second table… and those rows in the second table can also map to multiple (different) rows in the first table.

 

One-to-One Relationship

A One-to-One relationship means that you have two tables that have a relationship, but that relationship only exists in such a way that any given row from Table A can have at most one matching row in Table B.