Message-ID: <43E8AE37.1080205@anpe.fr>
Date: Tue, 07 Feb 2006 15:27:03 +0100
From: Patrick JACQUOT <patrick.jacquot@anpe.fr>
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Cc: pgsql-sql@postgresql.org
Subject: Re: problem referencing an attrib which is not unique
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Vic Rowan wrote:

>
>
> ---------- Forwarded message ----------
> From: *Vic Rowan* <mightymate@gmail.com <mailto:mightymate@gmail.com>>
> Date: Feb 7, 2006 2:31 PM
> Subject: problem referencing an attrib which is not unique
> To: pgsql-sql@postgresql.org <mailto:pgsql-sql@postgresql.org>
>
>
> hello everybody,
>
> I need some thing like this below for an application which stores log 
> messages in multiple languages. The table 'event_msg' stores 
> predefined messages in multiple languages which can be populated with 
> place holder values from the application. (These of course are 
> language independent). So, the event_id associates these predefined 
> messages from both the tables so that displaying a log message is as 
> simple as looking up the event_id from the 'logs' table and similarly 
> looking up the event_id and language from the 'event_msg' table to 
> retreive the predefined_msg with the correct language - the 
> application determines the lang from a settings file - and combining 
> them to display the log message.
>
> CREATE TABLE event_msg (
>   event_id varchar(30) NOT NULL,
>   language char(2) NOT NULL,
>   predefined_msg varchar(250) NOT NULL,
>   PRIMARY KEY (event_id, language)
> );
>
> CREATE TABLE logs (
>   id int NOT NULL,
>   event_id varchar(30) REFERENCES event_msg (event_id) NOT NULL, 
>   placeholder_values varchar(250),
>   priority varchar(20) NOT NULL,
>   timestamp Date NOT NULL,
>   primary key (id)
> );
>
>
> The problem I am facing is the event_id from logs is not able to 
> reference event_id from event_msg as its not unique.
> There are as many entries for each event_id as there are languages 
> supported in the 'event_msg' table.
> I would be glad if somebody could suggest some work around here to the 
> above structure. Or alternately do I need to alter the table structure 
> altogether and if so what is the better way of doing this?
>
> Thanks in advance for any help offered.
>
> Cheers,
> Vic Rowan.
>
I think you need three tables

 One to list the allowable events, which will be used as reference
CREATE TABLE eventlist (
  event_id varchar(30) PRIMARY-KEY
);

One to give the messages translations
CREATE TABLE messagetranslations(
 event-id varchar(30) references eventlist (event_id) NOT NULL
 language char(2) not null
 event-translation varchar(250)
 PRIMARY KEY (event_id, language)
);

and your log table
CREATE TABLE logs (
  id int NOT NULL,
  event_id varchar(30) REFERENCES eventlist (event_id) NOT NULL, 
  placeholder_values varchar(250),
  priority varchar(20) NOT NULL,
  timestamp Date NOT NULL,
  primary key (id)
);

btw,  event-id could be just an integer. If, as I  understand, event-id 
is so large a string,
it's probably because it contains the english name of the event.
Just put it in an occurrence of messagetranslation, with language = 'EN'
other thing : with only 2 chars as language id, how do you distinguish 
EN-US and EN-UK
(or whatever id  the latter can have assigned)?.

hth
P. Jacquot