You need a schema-less approach if you need to create these things at runtime. Relational databases really aren't such a good fit in these cases. You can shoe horn something into a RDBMS with EAV or datablobs, but it won't scale well.
If you're using Postgres 9.2.x or better, there is built in JSON data storage you could use. You can write stored procedures using PLV8, an embedded V8 javascript engine. It's also <flamebait>faster than MongoDB</flamebait> based on what I've read. On Sat, Oct 5, 2013 at 2:25 PM, Mark Wardle <[email protected]> wrote: > Thanks both, > > This advice is all very helpful. I might do some performance measurement > to see whether keeping horizontal inheritance is actually causing problems. > I think I'm batch fetching which should mean joining on multiple tables and > not a SELECT on each and every entity. > > The problem is that with single table inheritance, combining all data > forms, I will end up with a database table with 449 columns - which might > have its own set of problems! > > Out of curiosity, am I going to hit any problems combining approaches? > Using single table inheritance when there are many common properties and > using horizontal inheritance when the majority of properties are not shared. > > What I should do instead is write a generic entity which itself stores a > runtime-defined, stored in the database (and modelling in EOF) bunch of > properties in an NSDictionary and has logic provided a runtime chosen > delegate. Then I could create new data collection forms using a dedicated > UI and little overhead. Then we'd just set-up a bunch of D2W rules to ask > the generic entity for displayPropertyKeys etc. for the appropriate fake > entity. Anyone created fake entities like this either? > > Best wishes, > > Mark > > > On 4 Oct 2013, at 19:23, Chuck Hill <[email protected]> wrote: > > On 2013-10-04 11:06 AM, "Ramsey Gurley" wrote: > > Not to contradict Chuck (he is always right), > > > Will someone PLEASE tell my wife? > > > -- > Chuck Hill > Executive Managing Partner, VP Development and Technical Services > > Practical WebObjects - for developers who want to increase their overall > knowledge of WebObjects or who are trying to solve specific problems. > http://www.global-village.net/gvc/practical_webobjects > > Global Village Consulting ranks 13th in 2012 in BIV's Top 100 Fastest > Growing Companies in B.C! > > Global Village Consulting ranks 44th in 25th annual PROFIT 500 ranking of > Canada’s Fastest-Growing Companies by PROFIT Magazine! > > > -- > Dr. Mark Wardle > Consultant Neurologist, University Hospital Wales, Cardiff, UK > Email: [email protected] or [email protected] Twitter: @mwardle > Telephone: 02920745274 (secretary) or facsimile: 02920744166 > > > > > >
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