Wednesday, August 07, 2002

Data Modeling for Lake Survey Program.  At the DNR we take the ages, lengths, weights and annular distances of the first 25 fish of each species from each net.  Beyond the first 25 fish, there could be buckets and buckets of the same species which we record as bulk fish, which is the count and the total volume or weight of those fish.  From the first 25 fish we statistically estimate the ages and lengths of the bulk fish that we haven't measured.  The question today is whether to store these data in the database or to have them calculated on the fly each time the information is requested.  Good database design calls for no calculated fields to be stored so we will probably not store these.  However, these extrapolated data could be a little different each time a report is issued because the fish lengths and ages are based on probability.  This is a small part of the brain dump I recieved from our outgoing analyst, Denise, who did an amazing job taking apart the functionality and requirements of our lake survey program.  There is more... 11:56:03 PM    comment []