ORM: one or more vs. zero or more

[Rickard Axne]

I am trying to model with mandatory roles, eg a Person(Id) has
EmailAddres().

I would like to know what support ORM in visio has for these
relationships as it generates DDL. In the logical model, it doesn't seem
to matter whether I use "one or more" or "zero or more". As we may
require for Persons to have *at least one* email address (or possibly
several), this is of importance.

Of course, the bottom line is that the RDBMS we use, SQL Server doesn't
support circular references (deferred constraints etc) so I was just
wondering if visio creates any triggers or other means of enforcing my
constraint.

Also I find it strange that no warning occurs if the constraint is igonerd.

TIA

Rickard

 

[Scot Becker]

Hi Rickard,

I am trying to model with mandatory roles, eg a Person(Id) has
EmailAddres().

I would like to know what support ORM in visio has for these
relationships as it generates DDL. In the logical model, it doesn't seem
to matter whether I use "one or more" or "zero or more". As we may
require for Persons to have *at least one* email address (or possibly
several), this is of importance.

Of course, the bottom line is that the RDBMS we use, SQL Server doesn't
support circular references (deferred constraints etc) so I was just
wondering if visio creates any triggers or other means of enforcing my
constraint.

Also I find it strange that no warning occurs if the constraint is

igonerd.

This would appear to be a bug in the DDL generation. I am 90% sure the
previous version of the tool would have included a warning, generated a
stored procedure stub (for you to supply code for) in the DDL for this
constraint, and/or even the constraint itself (I can't test this because my
installation of VisioModeler is lacking drivers and I can't generate DDL).

I know that enforcing this kind of constraint was considered "expensive" and
thus might not be auto-generated, but I am almost positive that the tool
used to include a SP stub for it....

Chang (or anyone else from the Visio DB team), are you still prowling these
parts?

Scot.
................................................
Scot Becker

Orthogonal Software
www.orthogonalsoftware.com

ORM Blog: www.objectrolemodeling.com

To e-mail me, please use my first name at the domain listed above. All mail
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will likely be deleted without being read.

 

[Rickard Axne]

This would appear to be a bug in the DDL generation. I am 90% sure the
previous version of the tool would have included a warning, generated a
stored procedure stub (for you to supply code for) in the DDL for this
constraint, and/or even the constraint itself (I can't test this because my
installation of VisioModeler is lacking drivers and I can't generate DDL).

I know that enforcing this kind of constraint was considered "expensive" and
thus might not be auto-generated, but I am almost positive that the tool
used to include a SP stub for it....

Chang (or anyone else from the Visio DB team), are you still prowling these
parts?

Thanks Scot!