What's the best database structure to keep multilingual data?

Question

Possible Duplicate:
Schema for a multilanguage database

Here's an example:

[ products ]
id (INT)
name-en_us (VARCHAR)
name-es_es (VARCHAR)
name-pt_br (VARCHAR)
description-en_us (VARCHAR)
description-es_es (VARCHAR)
description-pt_br (VARCHAR)
price (DECIMAL)

The problem: every new language will need modify the table structure.

Here's another example:

[ products-en_us ]
id (INT)
name (VARCHAR)
description (VARCHAR)
price (DECIMAL)

[ products-es_es ]
id (INT)
name (VARCHAR)
description (VARCHAR)
price (DECIMAL)

The problem: every new language will need the creation of new tables and the "price" field is duplicated in every table.

Here's another example:

[ languages ]
id (INT)
name (VARCHAR)

[ products ]
id (INT)
price (DECIMAL)

[ translation ]
id (INT, PK)
model (VARCHAR) // product
field (VARCHAR) // name
language_id (INT, FK) 
text (VARCHAR)

The problem: hard?

Answer 1

Your third example is actually the way the problem is usually solved. Hard, but doable.

Remove the reference to product from the translation table and put a reference to translation where you need it (the other way around).

[ products ]
id (INT)
price (DECIMAL)
title_translation_id (INT, FK)

[ translation ]
id (INT, PK)
neutral_text (VARCHAR)
-- other properties that may be useful (date, creator etc.)

[ translation_text ]
translation_id (INT, FK)
language_id (INT, FK) 
text (VARCHAR)

As an alternative (not especially a good one) you can have one single field and keep all translations there merged together (as XML, for example).

<translation>
  <en>Supplier</en>
  <de>Lieferant</de>
  <fr>Fournisseur</fr>
</translation>