Re: How would i do this? - Mailing list pgsql-general

From Vince Vielhaber
Subject Re: How would i do this?
Date
Msg-id Pine.BSF.4.40.0112111522440.96989-100000@paprika.michvhf.com
Whole thread Raw
In response to How would i do this?  (John Hughes <johughes@shaw.ca>)
List pgsql-general
On Tue, 11 Dec 2001, John Hughes wrote:

> I am new to DB programming, so im not too sure about how to implement my DB.
>
> Here is what i need: a DB with tables of:
>
> 1. Students.
> 2. Classes
> 3. Teachers
> 4. Assignments
>
> Each teacher can be assigned a class, which is compromised of a list of
> students. Each class can be given assignments.
>
> Coming from a programming background, I could do this in c++ very easily. I
> actually started inmplementing it in a similar fasion: each student class
> teacher ect would have a uniqe id in the database, and, for example, a
> class would include an array of integer student id's.
>
> This seems really error prone, and not very efficient.
>
> what is a better implementation?

Don't think array.  Look at it from the other direction.

Each class has a name (prog101) a room#, teacherid, etc.  and a class id.
Each student has a name, etc. and the id of the class they're taking.

Then:  select name from student where classid = 4;

Where 4 could be the id for prog101.

That's the REALLY simplified version, but you get the idea.


Vince.
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