When we built our application in Chapter 3, Your First Application, we made use of relationships. Each cat in our application was of a particular breed. However, instead of storing the name of the breed next to every individual cat and potentially having the breed repeating numerous times, we created a separate breeds table and each cat's breed was a value that referred to the ID of a record in that table. This gave us an example of two types of relationships: a cat belongs to a breed, but a breed can have many cats. This is defined as a one-to-many relationship.
There are other types of relationships, for each of which Eloquent provides good support:
One-to-one
Many-to-many
Has-many-through
Polymorphic relations
Many-to-many polymorphic relations
Here, we will look through them with an example of each.