EctoLtree

A library that provides the necessary modules to support the PostgreSQL’s ltree data type with Ecto.

Quickstart

1. Add the package to your list of dependencies in mix.exs

If you are using Elixir >= v1.7 and Ecto ~> 3.2

def deps do
  [
    ...
    {:ecto_ltree, "~> 0.3.0"}
  ]
end

If you are using Ecto ~> 3.0

def deps do
  [
    ...
    {:ecto_ltree, "~> 0.2.0"}
  ]
end

If you are using Elixir v1.6 and Ecto ~> 2.1

def deps do
  [
    ...
    {:ecto_ltree, "~> 0.1.0"}
  ]
end

2. Define a type module with our custom extensions

Postgrex.Types.define(
  MyApp.PostgresTypes,
  [EctoLtree.Postgrex.Lquery, EctoLtree.Postgrex.Ltree] ++ Ecto.Adapters.Postgres.extensions()
)

3. Configure the Repo to use the previously defined type module

  config :my_app, MyApp.Repo,
    adapter: Ecto.Adapters.Postgres,
    username: "postgres",
    password: "postgres",
    database: "my_app_dev",
    hostname: "localhost",
    poolsize: 10,
    pool: Ecto.Adapters.SQL.Sandbox,
    types: MyApp.PostgresTypes

4. Add a migration to enable the ltree extension

defmodule MyApp.Repo.Migrations.CreateExtensionLtree do
  use Ecto.Migration

  def change do
    execute("CREATE EXTENSION ltree",
            "DROP EXTENSION ltree")
  end
end

5. Add a migration to create your table

defmodule MyApp.Repo.Migrations.CreateItems do
  use Ecto.Migration

  def change do
    create table(:items) do
      add :path, :ltree
    end

    create index(:items, [:path], using: :gist)
  end
end

6. Define an Ecto Schema

defmodule MyApp.Item do
  use Ecto.Schema
  import Ecto.Changeset
  alias EctoLtree.LabelTree, as: Ltree

  schema "items" do
    field :path, Ltree
  end

  def changeset(item, params \\ %{}) do
    item
    |> cast(params, [:path])
  end
end

7. Usage

iex(1)> alias MyApp.Repo
MyApp.Repo
iex(2)> alias MyApp.Item
MyApp.Item
iex(3)> import Ecto.Query
Ecto.Query
iex(4)> import EctoLtree.Functions
EctoLtree.Functions
iex(5)> Item.changeset(%Item{}, %{path: “1.2.3”}) |> Repo.insert!
%MyApp.Item{
  __meta__: #Ecto.Schema.Metadata<:loaded, “items”>,
  id: 1,
  path: %EctoLtree.LabelTree{labels: [“1”, “2”, “3”]}
}
iex(6)> from(item in Item, select: nlevel(item.path)) |> Repo.one
3

The documentation can be found at hexdocs.

Copyright and License

Copyright (c) 2018-2019 Jose Miguel Rivero Bruno

The source code is licensed under The MIT License (MIT)