> > Either there is a documented interface to a persistence layer, or there isn't. > It is quite possible I missed it in the documentations > But till now, I asked it three times in three days, is there a documented > interface to a persistence layer? Or do I have to puzzle it myself, which is > possible, but I do not want to invent a wheel which is already there. >
As far as I am aware there is no fixed specification for a persistence layer. From a brief chat to Thomas he indicated that a variety of database styles were being used in live projects e.g traditional relational databases, 'shredded' row storage such as OpenSDE, OO databases such as db40 and cache, XML file/stream storage or newer hybrids such as Sql Server 2005. I suspect there is no correct way of doing this. It will depend on circumstances and very rapidly changing persistence options. The whole industry is moving to lessening the 'impedance' between structured OO modeled code and the underlying persistence layer and as yet there does not appear to be a single universally compelling option. Ian
