Questions on Tags table schema

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От Jay Kang
Тема Questions on Tags table schema
Дата
Msg-id d251ee4a0707290722k50de5789lad616cb168791058@mail.gmail.com
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Ответы Re: Questions on Tags table schema
Re: Questions on Tags table schema
Список pgsql-performance
Hello,

I'm currently trying to decide on a database design for tags in my web 2.0 application. The problem I'm facing is that I have 3 separate tables i.e. cars, planes, and schools. All three tables need to interact with the tags, so there will only be one universal set of tags for the three tables.

I read a lot about tags and the best articles I found were:

Road to Web 2.0 ( http://wyome.com/docs/Road_to_Web_2.0:_The_Database_Design  )
tags: database schema ( http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html  )

and a forum discussion on tags with a very similar problem:
http://www.webmasterworld.com/forum112/502.htm 
But I don't like the solution, would like to stick with serial integer for Cars, Planes and Schools tables.

Currently, this is my DB design:

Cars (carid, carname, text, etc.)
Planes (planeid, planename, text, etc.)
Schools (schoolname, text, etc.) <------ School does not take int as primary key but a varchar.

Tags (tagid, tagname, etc)
 
--- Now here is where I have the question. I have to link up three separate tables to use Tags
--- So when a new car is created in the Cars table, should I insert that carID into the TagsItems table
--- as itemID? So something like this?

TagsItems
(
  tagid INT NOT NULL REFERENCES Tags.TagID,
  itemid INT NULL,  <---- really references Cars.carID and Planes.planeID
  schoolname varchar NULL  <---- Saves the Schools.schoolname
  itemid + tagId as Unique
)

I also have a question on the schoolname field, because it accepts varchar not integer. There seems to be some design that would better fit my needs. I'm asking  you guys for a little assistance.

--
Regards,
Jay Kang

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