Also consider the demands of a very very rapidly changing field, like medical informatics. In this area, many prefer the flexibility of a key/value system because adding columns constantly would be a nightmare. Think off adding columns for every new lab test, imaging type, procedure, etc. This is where a system like this is extremely helpful.
Another addition that can sometimes be helpful is to add an additional column that holds a "datatype" that represents a traditional database constraint. This allows for easy programmatic testing against this datatype before the data enters the database. Obviously this requires some programming work up-front, but this can be exceedingly useful once it is built. Again, flexibility is the key here. Some links: http://ycmi.med.yale.edu/nadkarni/eav_CR_contents.htm http://www.cdc.gov/nedss/DataModels/index.html http://www.research.ibm.com/journal/sj/461/eggebraaten.html Andrew --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
