# Getting Started With Ash Parental
Ash Parental is an Ash Framework extension that brings STI(Single Table Inheritance) capability to your resource.
If you want to learn how to build Ash extensions like this you can read more in the Ash Framework for Phoenix Developers serie on medium https://medium.com/p/62b58b426246.
## What is a single table inheritance (STI)?
It's a fancy name for a simple concept: Extending a resource (usually to add specific behavior), but referencing the same table.
## Installation
The package can be installed by adding `ash_parental` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:ash_parental, "~> 0.1.0"}
]
end
```
Then add it to your resource like below
```elixir
defmodule MyApp.Comment do
use Ash.Resource, extensions: [AshParental]
....
end
```
## What AshParental Does
This extension adds:
1. `parent_id` attributes to your resource
2. belongs to `parent` relationship
3. has many `children` relationship
4. `children_count` aggregates
## Configurations
It comes with 2 configurations:
1. `children_relationship_name` to rename children relationship name
2. `destroy_with_children?` to indicate whether or not parents should be destroyed with their children
```elixir
defmodule MyApp.Comment do
use Ash.Resource,
domain: MyApp.Domain,
data_layer: Ash.DataLayer.Ets,
# <--- Add AshParental to your resource
extensions: [AshParental]
ets do
table :comments
end
# <--- Configure Ash Parental
ash_parental do
children_relationship_name :replies # Default: children
destroy_with_children? true # Default: false
end
actions do
defaults [:create, :read, :update, :destroy]
end
attributes do
uuid_primary_key :id
attribute :content, :string, allow_nil?: false
timestamps()
end
end
```
