Hello all, recently, I read a good article from :

http://www.geekgirls.com/databases_from_scratch_3.htm

I have some question in my mind to achieve this.

In Step 11: Test sample data., Participants Table, a student may have
more than one registered activities.

Student ID Activities
----------------------------------------
12 Swimming
12 Jogging
13 Reading
14 Swimming
12 Swimming -> How we can prevent this
duplicated information???

May I know, how I can prevent the last duplicated col. Is there any
rule I can set through SQL command? Or I have to perform this
prevention through my own appplication code?

Thanks!

cheok

On Jul 23, 11:42 am, yancheng.ch... (AT) gmail (DOT) com wrote:
Activity.