The ORM Foundation

Hi, Can someone tell me why ORM objects generate what looks like superfluous cancatenation for column names in the DDIL script files? Even in very simple models, without nesting, or ring constraints, I see column names in the form: Xxxxx_Xxxxx_Name, or Yyyy_Yyyy_Code, etc.... It doesn't look as though the method is used to prevent duplicate ...

> Actually, I do think that a deontic constraint should be implemented Yes, I agree - but it cannnot be enforced mandatorily. There's no standard ''warning'' system in SQL or semantics defining what should happen when a warning occurs, which is why I said: ''Should mostly be true, I'll enforce it, make it easy for me to do it''. The ...

Hi, Whether a warning or fatal error is the effect you want, when a constraint is violated, depends on the target of the modeling. As I am most concerned with modeling RM compliant relational database schemas, I don't want anything to get by that would break compliance and open the DB to data integrity errors. As ORM can be used for other ...

Actually, I do think that a deontic constraint should be implemented. An alethic constraint is verbalized in terms of ''must''; e.g. a race horse must have exactly one trainer. If you break an alethic constraint an error should be issued and the operations should be denied. A deontic constraint is verbalized in terms of ''should''; e.g. a race ...

Hi, Thanks for the reply. I was curious about how a deontic constraint was implemented. Apparently, it's not - unless you implement it in some manor outside of the scope of what the tool will generate. That's Ok, as long as clearly denoted as such. Maybe there should be a method of marking these constraints on the diagram (color from red to ...

Hi, I had just looked at the associated .xml files and seen the warning about the 'SubsetConstraint1' having gone missing in action, and was going to point that out to you! You beat me to the punch. Though I'm not pleased that a feature as important as this one isn't implemented yet, (it would be helpful if any feature not yet implemented was ...

I haven't used deontic modality in ORM, but I have used it elsewhere (like in my data layer generator). Basically it's saying to the tool ''Don't enforce this constraint because it may occasionally or temporarily get violated - I'll enforce this one myself!''. In other words, don't generate SQL that enforces it, leave enforcement to the business ...

On looking at it again, it's pretty simple; the subset constraint is not reflected in the SQL Server code at all. It's just a ''feature not implemented'', and I've submitted an feature request for it (including my ORM file; you could download that and take a look). A proper implementation requires the use of SQL triggers. Based on your ...

Hi, I'll look through the model again. You may ve right in that the fault is with the way the tool implements the subset constraint, but the bottom line is that the methodology-domain logic-tool system doesn't produce a solution for the test problem we're looking at. Yes,the mapping algorthims used are essencial parts of the solution. I ...

> I put an IUC to show that a student can enroll in at most one School. This constraint true, but isn't necessary once you have the subset constraint in place. It says that a student may not participate in an activity more than once (sanctioned by different schools). But since they can only be enrolled in one school, and can only ...