>>>>> "Ted" == Ted Byers <r.ted.byers@xxxxxxxxxx> writes: Ted> Here is a general question relating to this. The problem involves due Ted> diligence related to environmental protection. Consider a distributed Ted> application to support this. You have a facility with an Ted> environmental monitoring program. Samples are taken from soil, water Ted> and air and sent off-site for analysis. Each sample, when analyzed, Ted> results in a report sent to the facility's management for their Ted> records. However, if the concentration of some contaminant in a Ted> sample is above some threshold, a second report, containing the Ted> complete analysis results for the sample, is generated and sent to one Ted> or more people, both inside and outside the organisation Ted> (e.g. engineers within the organization responsible for fixing Ted> problems with the facility and engineers at relevant regulatory Ted> agencies). One objective is to automate as much of the data management Ted> as possible and to ensure that if a problem arises everyone who needs Ted> to know about it is notified. The process has to be auditable, so Ted> that information about when each step in the process starts is stored Ted> in the database, as well as information about when messages are Ted> acknowledged (again automated - so when an engineer opens a message Ted> about a problem, an acknowledgement is sent to the database without Ted> his intervention). Ted> I suppose email might work as a means of sending messages, but I was Ted> thinking of Sun's JMS instead, working with triggers. I could then Ted> create my own thin client to display the reports, perhaps sorting them Ted> according to user specified criteria. I can see how to do it within Ted> the web tier, or within the client tier (within the labs doing the Ted> analyses). The thing is, of the designs I have considered, the one Ted> involving triggers with JMS on the main supporting website (with a Ted> database back end) is the simplest in terms of deployment, since all Ted> interested parties could interact with the application through the Ted> internet using a very thin client (perhaps even with an applet within Ted> a web page) and I would not need to worry about deploying software to Ted> all relevant people/sites. Ted> If you faced this problem, what would you do, and why? As already proposed, I'd have a trigger noticing the exceptional condition post a record to an audit log table (and use NOTIFY). Then I'd have a notification process manage watching that table, and send the notices as needed. That's the right level for this. Database triggers should be about adding rows, deleting rows, and modifying values in rows to manage integrity. It's the middleware that's responsible for repackaging that or acting on changed data. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn@xxxxxxxxxxxxxx> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
