# Ecto Associations

## Player

```elixir
schema "players" do
  many_to_many :games, Game, join_through: Gameplay
  has_many :gameplays, Gameplay
  # ...
end

def changeset(%Player{} = player, attrs) do
  player
  |> cast_assoc(:games)
  |> Ecto.build_assoc(:gameplays)
  |> cast(...)
  # ...
end
```
## Game

```elixir
schema "games" do
  many_to_many :players, Player, join_through: Gameplay
  has_many :gameplays, Gameplay
  # ...
end

def changeset(%Game{} = game, attrs) do
  game
  |> cast_assoc(:players)
  |> Ecto.build_assoc(:gameplays)
  |> cast(...)
  # ...
end
```

## Gameplay

```elixir
schema "gameplays" do
  belongs_to :game, Game
  belongs_to :player, Player
  # ...
end

def changeset(%Gameplay{} = gameplay, attrs) do
  gameplay
  |> cast(...)
end
```