Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

MS Visio Entity Relationship Diagram (ERD) doesn't allow multiple foreign keys from the same entity pointed by the same primary key

Posted on 2006-11-05
3
3,966 Views
Last Modified: 2008-01-09
I have a 'material' table and a 'composition'  table.
'composition' has 2 foreign keys: 'Input' and 'Product'.
'material' primary key is 'Id'.
I created two 1 to many relationships: Id --> Input and Id --> Product.

Although this works well in "real life" (in the database schema), I was not able to represent it in Visio 2003 using the ERD database modeling tool. If I try to associate Id to Product after having associated Id to Input, Visio simply changes the previous association to the new one. I can never have both at once. (I am not using reverse engineering at this point)

How can I document this ERD with Visio?

thanks,

Ricardo
0
Comment
Question by:romaciel
  • 2
3 Comments
 
LVL 16

Expert Comment

by:muzzy2003
ID: 17877407
You're pointing the arrows in the wrong direction, aren't you? Try dragging them in the opposite direction.
0
 

Author Comment

by:romaciel
ID: 17877735
Thanks, I indeed misrepresented the association.  
The symbol could be something like Id --< Input and Id --< Product, with < standing for crow's feet.

The relationship I unsuccefully  tried to build in Visio was material PK (Id)  one to many composition FK(Input)  AND
material PK(Id) one to many composition FK(Product).

The relationships above describe materials that can simultaneously be products or inputs (raw materials). 'composition' is the association table that associates one material as a product with (one of) its input(s).

I can have either, not both relationships, in Visio database modeling.
0
 
LVL 16

Accepted Solution

by:
muzzy2003 earned 500 total points
ID: 17877754
You can have the two foreign keys you mention, but Visio may insist on you specifying different verbs describing the associations (defaults are "has" and "is a" I think off the top of my head). I don't have Visio installed on the PC I'm at right now, but can you describe how you are creating these relationships? Are you dragging two new relationship connectors onto the diagram and then connecting them?
0

Featured Post

Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I annotated my article on ransomware somewhat extensively, but I keep adding new references and wanted to put a link to the reference library.  Despite all the reference tools I have on hand, it was not easy to find a way to do this easily. I finall…
Today companies are subjected to more-and-more data, and it won't stop any time soon.  But there are obvious opportunities for reducing data, particularly data duplicated among companies.
This video demonstrates basic masking and how to edit the mask to reveal the desired image.
Viewers will learn how to use the Hootsuite Dashboard.

789 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question