Jay Kang wrote:
Hello,
I'm currently trying to decide on a database design for tags in my web
2.0application. 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 )
And what in particular recommended this to you?
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.
You don't mention a primary-key here at all. You're not thinking of
using "schoolname" are you?
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
)
What's wrong with the completely standard:
car_tags (carid, tagid)
plane_tags (planeid, tagid)
school_tags (schoolid, tagid)
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.
Sorry, don't understand this question.
--
Richard Huxton
Archonet Ltd
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