Trans provides a way to manage and query translations embedded into schemas
and removes the necessity of maintaining extra tables only for translation storage.
It is inspired by the great hstore translate
gem for Ruby.
Trans is published on hex.pm and the documentation
is also available online. Source code is available in this same
repository under the Apache2 License.
On April 17th, 2017,
Trans was featured in HackerNoon
Having Ecto SQL and Postgrex in your application will allow you to use the
component to generate database queries based on translated data. You can still
Trans.Translator component without those dependencies though.
- Ecto SQL 3.0 or higher
- PostgreSQL 9.4 or higher (since
Transleverages the JSONB datatype)
The traditional approach to content internationalization consists on using an
additional table for each translatable schema. This table works only as a storage
for the original schema translations. For example, we may have a
This approach has a few disadvantages:
- It complicates the database schema because it creates extra tables that are coupled to the "main" ones.
- It makes migrations and schemas more complicated, since we always have to keep the two tables in sync.
- It requires constant JOINs in order to filter or fetch records along with their translations.
The approach used by
Trans is based on modern RDBMSs support for unstructured
datatypes. Instead of storing the translations in a different table, each
translatable schema has an extra column that contains all of its translations.
This approach drastically reduces the number of required JOINs when filtering or
Trans is lightweight and modularized. The
Trans module provides metadata
that is used by the
Trans.QueryBuilder modules, which
implement the main functionality of this library.
Imagine that we have an
Article schema that we want to translate:
defmodule MyApp.Article do use Ecto.Schema schema "articles" do field :title, :string field :body, :string end end
The first step would be to add a new JSON column to the table so we can store the translations in it.
defmodule MyApp.Repo.Migrations.AddTranslationsToArticles do use Ecto.Migration def change do alter table(:articles) do add :translations, :map end end end
Once we have the new database column, we can update the Article schema to include the translations
defmodule MyApp.Article do use Ecto.Schema use Trans, translates: [:title, :body] schema "articles" do field :title, :string field :body, :string embeds_one :translations, Translations, on_replace: :update, primary_key: false do embeds_one :es, MyApp.Article.Translation, on_replace: :update embeds_one :fr, MyApp.Article.Translation, on_replace: :update end end end defmodule MyApp.Article.Translation do use Ecto.Schema @primary_key false embedded_schema do field :title, :string field :body, :string end end
After doing this we can leverage the Trans.Translator and Trans.QueryBuilder modules to fetch and query translations from the database.
The translation storage can be done using normal
Ecto.Changeset functions just like any other fields.
Is Trans dead?
Trans has a slow release cadence, but that does not mean that it is dead. Trans can be considered as "done" in the sense that it does one thing and does it well.
New releases will happen when there are bugs or new changes. If the last release is from a long time ago you should take this as a sign of stability and maturity, not as a sign of abandonment.