Multilingual Apps and Translations

Introduction

Use view entities to create apps that provide translations for your users.

Use Case

For this purpose of this use case, the following domain model is used:

The entity ProductTranslation contains a translation of a product’s description to a language indicated by LanguageCode. LanguageCode is a standard 5-letter language-country code (for example, en_US, nl_NL, ko_KR).

The descriptions in the default language (in this example, en_US) are stored in the Product entity, whereas translated descriptions (nl_NL and ko_KR) are stored in ProductTranslation.

Create an Overview Page

To use a view entity that translates languages, ensure your app supports multiple languages. Follow the steps below:

1. Open your App Settings and click the Languages tab.
2. Click Add and use the drop-down to select the language (or languages) you want to include in your app.
3. Click OK > OK.

Combine the languages in the two entities into a single view. To do this, join the Product and ProductTranslation entities by creating a new view entity.

1. Open your domain model and add a new view entity named AllProductTranslationVE.

2. Add the following query for your entity:

   SELECT
       p.ProductId as ProductId,
       p.ProductName as ProductName,
       p.QuantityPerUnit as QuantityPerUnit,
       p.Discontinued as Discontinued,
       pt.LanguageCode as LanguageCode,
       coalesce(pt.Description, p.Description) as Description
   FROM Shop.Product p
       JOIN p/Shop.ProductTranslation_Product/Shop.ProductTranslation pt
   UNION
   SELECT
       p.ProductId as ProductId,
       p.ProductName as ProductName,
       p.QuantityPerUnit as QuantityPerUnit,
       p.Discontinued as Discontinued,
       cast('en_US' as STRING) as LanguageCode,
       p.Description as Description
   FROM Shop.Product p
   

   

3. Filter the translation that corresponds to the user’s current language by creating a new view entity. Name this new entity TranslatedProductVE.

4. Add the query below to your entity:

   SELECT
       pt.ProductId as ProductId,
       pt.ProductName as ProductName,
       pt.QuantityPerUnit as QuantityPerUnit,
       pt.Discontinued as Discontinued,
       pt.LanguageCode as LanguageCode,
       pt.Description as Description
   FROM Shop.AllProductTranslationVE pt
       LEFT JOIN System.User as u on (u.ID = '[%CurrentUser%]')
       LEFT JOIN u/System.User_Language/System.Language as l
   WHERE (l.Code = pt.LanguageCode)
   

   

Alternatively, you can also combine the view entities into one with a nested query:

SELECT
  cp.ProductId as ProductId,
  cp.ProductName as ProductName,
  cp.QuantityPerUnit as QuantityPerUnit,
  cp.Discontinued as Discontinued,
  cp.Description as Description,
  cp.LanguageCode as LanguageCode
FROM
(
  SELECT
    p.ProductId as ProductId,
    p.ProductName as ProductName,
    p.QuantityPerUnit as QuantityPerUnit,
    p.Discontinued as Discontinued,
    pt.LanguageCode as LanguageCode,
    coalesce(pt.Description, p.Description) as Description
  FROM Shop.Product p
    JOIN p/Shop.ProductTranslation_Product/Shop.ProductTranslation pt
  UNION
  SELECT
    p.ProductId as ProductId,
    p.ProductName as ProductName,
    p.QuantityPerUnit as QuantityPerUnit,
    p.Discontinued as Discontinued,
    cast('en_US' as STRING) as LanguageCode,
    p.Description as Description
  FROM Shop.Product p
) as cp
  LEFT JOIN System.User as u on (u.ID = '[%CurrentUser%]')
  LEFT JOIN u/System.User_Language/System.Language as l
WHERE (l.Code = cp.LanguageCode)

5. Generate an overview page for the view entity by right-clicking TranslatedProductVE > Generate overview pages.
6. Open the new page and remove the columns you do not need from the data grid.
7. Run your app locally. You should see the product description in the language that corresponds to the user’s current language.