Update the Links model to have a unique shorten.

CHANGELOG.org

@@ -3,4 +3,6 @@
     Init project.
     Added the Links model.
     Added README and CHANGELOG.
+** 0.1.1 <2023-07-06 Thu>
+    Updated the Links model to have a unique shorten.
 

lib/link_shortener/links.ex

@@ -8,6 +8,7 @@ defmodule LinkShortener.Links do
   schema "links" do
     field :name, :string
     field :url, :string
+    field :shorten, :string
 
     timestamps()
   end
@@ -15,8 +16,9 @@ defmodule LinkShortener.Links do
   @doc false
   def changeset(link, attrs) do
     link
-    |> cast(attrs, [:name, :url])
-    |> validate_required([:name, :url])
+    |> cast(attrs, [:name, :url, :shorten])
+    |> validate_required([:url, :shorten])
+    |> unique_constraint(:shorten)
   end
 
   def new_one(), do: Links.changeset(%Links{})

priv/repo/migrations/20230704184320_create_links.exs

@@ -5,8 +5,11 @@ defmodule LinkShortener.Repo.Migrations.CreateLinks do
     create table(:links) do
       add :name, :string
       add :url, :string
+      add :shorten, :string
 
       timestamps()
     end
+
+    create unique_index(:links, [:shorten])
   end
 end