# Relations
One of the most amazing things about Ruby on Rails is how easy it is to create relations (Active Record associations (opens new window)) between models. We try to keep the same simple approach in Avo too.
At the moment, Avo supports four relation types.
# Belongs to
belongs_to :user
When you add a BelongsTo relation to a model, you will see three different field types.
On the Index view, you'll see a column with the @title value of the associated model.
On the Show view, you'll see a link to the associated model.
On the Edit and Create views, you'll see a drop-down element with the available records. Here you may change the associated model.
# Has One
The HasOne relation works similarly to BelongsTo.
has_one :admin
# Has Many
The HasMany field is visible only on the Show page. Below the regular fields panel, you will see a new panel with the model's associated records.
has_many :projects
Here you may attach more records by clicking the "Attach" button.
In a similar fashion, you may detach a model using the detach button.
# Has And Belongs To Many
The HasAndBelongsToMany relation works similarly to HasMany.
has_and_belongs_to_many :users