[AccessD] Maximum number of columns in a table ?

Stuart McLachlan stuart at lexacorp.com.pg
Fri Feb 7 22:06:01 CST 2003


Just to get us thinking.

For junction tables, I never use a separate  (Hey Drew - I spelt it right first time <g>) PK.
Just the two IDs as a unique index. It's never bitten me yet.

Anyone have a good reason for the PK in this case?

> A junction table effects a many2many relationship. Students and Courses;
> many of each other. So you create a junction table tblCourseStudents
> consisting of an ANPK, a CourseID and a StudentID, with the latter pair
> indexed unique so you can't enroll a kid twice in Shotokan Karate 101.
> Many kids take many courses. Many courses contain many kids. The junction
> table gives you all the data in either direction.
> 
> -----Original Message-----
> From: accessd-admin at databaseadvisors.com
> [mailto:accessd-admin at databaseadvisors.com] On Behalf Of Oleg_123 at xuppa.com
> Sent: February 7, 2003 2:51 PM
> To: accessd at databaseadvisors.com
> Subject: Re: [AccessD] Maximum number of columns in a table ?
> 
> I know that right way usually takes longer to develop :))
> Whats a junction table ?
> I remember when I took SQL class, professor said never to have a table
> that contains data gotten from other table through math manipulations..
> I was thinking about having a table with coumns 1,2,3,4,5,6,7,8,9 ---> 78
> And then a a query with columns 2,3, 4-6, 7-12, etc.
> I'll read the article that u send again
> 

-- 
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http://www.lexacorp.com.pg
Information Technology Consultancy, Software Development,System Support.






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