Cross-cutting I18N native support in databases

Question

Does a database engine with native cross-cutting internationalization support exist, able to store data like this?

SET LOCALE='en'
SELECT * FROM BOOKS

+------+-----------------------+----------------+
|  ID  | TITLE                 | AUTHOR         |
+------+-----------------------+----------------+
|   1  | The Lord of The Rings | J.R.R. Tolkien |
+------+-----------------------+----------------+

SET LOCALE='it'
SELECT * FROM BOOKS

+------+-------------------------+----------------+
|  ID  | TITLE                   | AUTHOR         |
+------+-------------------------+----------------+
|   1  | Il Signore degli Anelli | J.R.R. Tolkien |
+------+-------------------------+----------------+

i.e. able to store values in a third dimension, such as a locale in this case?

Clarification

In the example above, just TITLE should be affected by SET LOCALE by a special definition in this kind of database (I imagine something like LVARCHAR); so, adding a discriminator column would not be feasable since all the non-localized columns will be duplicated.

Answer 1

With PostgreSQL you can simulate something like using views and environment variables.

create table books_ids(
  book_id serial not null primary key,
  author text not null);

create table books_titles (
  book_id int not null references books_ids,
  lang char(2) not null,
  title text not null,
  isbn text null,
  primary key(book_id, lang));

insert into books_ids (author) VALUES ('J.R.R. Tolkien');
insert into books_titles (book_id, lang, title)
  values (1, 'en', 'The Lord of The Rings'), (1, 'it', 'Il Signore degli Anelli');

create view books as
  select b.book_id as id, t.title, b.author
  from books_ids b
  join books_titles t on (t.book_id = b.book_id and t.lang = current_setting('my.lang'));

-- in English
set my.lang='en'; select * from books;

-- in Italian
set my.lang='it'; select * from books;