| From: | "Daniel McBrearty" <danielmcbrearty(at)gmail(dot)com> | 
|---|---|
| To: | pgsql-general(at)postgresql(dot)org | 
| Subject: | table has many to many relationship with itself - how to implement? | 
| Date: | 2006-06-14 08:53:36 | 
| Message-ID: | 9cf113670606140153u77966431o1a3f5919d0405fae@mail.gmail.com | 
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| Thread: | |
| Lists: | pgsql-general | 
Hi all,
I have a table "phrases" that looks like this :
create table phrases(
 id serial ,
 language integer references langauges(id),
 content text
);
Simply a word or phrase in some language.
Now I want to express the concept of a "translation". A translation is
a number of phrases from different languages that are a translation of
each other. There is nothing else to say about a translation - though
it does need to be referencable by other tables, so it needs an ID.
One way to do this is with these two tables:
create table translations (
 id serial primary key
);
create table translations_to_phrases (
 translation_id integer references translations(id),
 phrase_id integer references phrases(id),
 primary key (translation_id, phrase_id)
);
Now this actually works as a data structure; the translations table is
a bit odd, having only an id, but that is all we really need.
Can I do this though? can I create a row in translations?
insert into table translations ... insert what?
The other way to do this that I see is to lose the link table
translations_to_phrases, and then make translations
create table translations (
 id serial primary key,
 phrases integer[]
);
but it seems that I can no longer make postgre aware that the integers
in translations(phrases) are references.
What is the best solution?
Thanks
Daniel
-- 
Daniel McBrearty
email : danielmcbrearty at gmail.com
www.engoi.com : the multi - language vocab trainer
BTW : 0873928131
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