Wolfgang wrote in post #1000187: > STI is a good approach, but my "subtables" have additional attributes > and afaik this isn't supportet by STI, is it? > > For example: > > user << Base > id > firstname > lastname > address > end > > employee << user > <all of the above and additionally:> > salary > end
In the past I used a framework that supported other techniques besides Single-Table Inheritance. There were actually two other options that were called Horizontal and Vertical Inheritance. Of those options Vertical Inheritance was the closest to what we think of as object inheritance (as you described above), but was also the least efficient. The issue is that both Horizontal and Vertical inheritance require multiple queries to get to all the data you need, which causes performance problems. Even with a framework that supported the other techniques, using STI was strongly recommended. The performance costs of either Horizontal or Vertical was simply too high. Inheritance doesn't map well to RDBMS. The cost of the null fields in a single table that contains all attributes for the entire inheritance hierarchy is negligible compared to the other techniques. -- Posted via http://www.ruby-forum.com/. -- 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.
