# `BoxTurtle.Schema.Ecto.Ksuid`
[🔗](https://github.com/twajjo/box_turtle/blob/v0.1.0/lib/schema/ecto/ksuid.ex#L1)

An `Ecto.Type` for [KSUID](https://github.com/segmentio/ksuid) keys, stored as 27-character base62 strings.
KSUIDs sort by creation time, which makes them convenient primary keys.

    defmodule MyApp.Blog.Tag do
      use Ecto.Schema

      # Generated on insert; @foreign_key_type makes belongs_to fields KSUIDs too.
      @primary_key {:id, BoxTurtle.Schema.Ecto.Ksuid, autogenerate: true}
      @foreign_key_type BoxTurtle.Schema.Ecto.Ksuid

      schema "tags" do
        field :name, :string
      end
    end

    # The migration stores the key as a string column.
    defmodule MyApp.Repo.Migrations.CreateTags do
      use Ecto.Migration

      def change do
        create table(:tags, primary_key: false) do
          add :id, :string, size: 27, primary_key: true
          add :name, :string, null: false
        end
      end
    end

    {:ok, tag} = MyApp.Repo.insert(%MyApp.Blog.Tag{name: "elixir"})
    tag.id #=> "2Ux8k3WmS1mXJ9i1QeB6LcPq0Zf"

# `embed_as`

# `equal?`

# `valid?`

```elixir
@spec valid?(term()) :: boolean()
```

True for a 27-character base62 string.

---

*Consult [api-reference.md](api-reference.md) for complete listing*