romaciel
asked on
MS Visio Entity Relationship Diagram (ERD) doesn't allow multiple foreign keys from the same entity pointed by the same primary key
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
'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
You're pointing the arrows in the wrong direction, aren't you? Try dragging them in the opposite direction.
ASKER
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.
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.
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