Dynamic filename in Business Rules

Question

Hi,
I would like to use the DataExport command in my business rules to extract level-0 data in a file as a reference for user. I would need to extract data only for Entities that a user has access to (I figured that I could use parameters, link the rule to a Planning form and use "members" on form).
My problem is that I would need a different filename for each execution. Something like :
..\userABC_20090513_100350_BV_SBQ.txt
..\userDEF_20090513_100430_BV_SLVQ.txt
Is there a way, in business rules, to find the following info ?
- the user who is currently running the rule.
- the current date.
- the current time.
If not, is there a way to include a shell in a business rule. I have a small .exe that return the date or time as an "errorlevel" code that I could use if I can call a shell in the rule.
Finally, a theorical question : is there an other way to ensure that only the user who run the rule can access the generated file (always while using business rules) ?
Thanks

Answer 1

First, in a well designed data model, I'm not sure I see the need for data validation logic to change regularly. If a particular column cannot be NULL today, it would be rather unlikely that it would somehow need to be NULL tomorrow.
Second, I'm not sure I see what this approach buys you over the much simpler approach of adding and removing check constraints if the data model changes. Adding and removing a constraint is pretty trivial-- orders of magnitude less difficult than doing the analysis to determine what constraint needs to change and what impact that has downstream.
Third, I would suspect that if you need to encode these sorts of constrains in a table, your system will kill downstream systems with regularity. If p1 is NOT NULL today, but tomorrow it suddenly allows NULL values, a consumer application might well break (or worse, silently return incorrect results). Data changes should not be able to screw up downstream systems.
Fourth, if you did build such a system, you would have to build your own constraint validator, rather than being able to rely on Oracle's (unless you wrote code to create and drop Oracle constraints based on values in a table, but that seems rather convoluted). Given that Oracle's constraint validation engine is highly optimmized and highly accurate, a home grown engine isn't going to look particularly good in comparison.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC