So a find by primary key, navigation, or query would have the appropriate WHERE clauses generated with no action on the part of the user.
In the example below, the A instance doesn't need to worry about which B it refers to, because the B instances corresponding to A's time are also selected automatically, in that both A and B have corresponding temporal WHERE clauses based on the same time.
Craig On May 21, 2007, at 3:16 PM, Ricardo Andere de Mello wrote:
yes.... this look something simple, but it is not...see, objects exists in time, so for example, they are not deleted, they are"finalized".the worst part are the relationships, because they are historical too... basically you have a start and end date for that object, and the object withend date null is the actual object.everytime you modify an object you clone it, set the end date of the old,and set the start date of the new.imagine now that "A" points to "B". both are historical objects. if "B" is modified, a new historical object is created. "A" should point to the new "B", not the old one. so you must have a "historical id" or a "historical idobject" to point at, that is common to all "B". []s, gandhi 2007/5/21, Marc Prud'hommeaux <[EMAIL PROTECTED]>:Something like: "select x from Employee x as x was on January 1, 2002"On May 21, 2007, at 11:01 AM, Kevin Sutter wrote: > Sorry to show my ignorance, but what are "historical objects"? > Thanks! > > Kevin > > On 5/18/07, Ricardo Andere de Mello <[EMAIL PROTECTED]> wrote: >> >> ok, I'm sending this message to netmind list too, so they can >> answer my >> next >> question too: >> >> * Maybe this is a silly question, but is it possible to place >> netmind's >> beankeeper historical structure between OpenJPA and the database >> backstore? >> >> I dont think *any* serious commercial application can avoid >> historical >> objects. >> I think netmind's beankeeper is a great thing, and JPA is a good >> standard. >> Mixing both projects would be very cool. ;-) >> >> []s, gandhi >> >> >> 2007/5/18, Marc Prud'hommeaux <[EMAIL PROTECTED]>: >> > >> > >> > Sadly, no. We don't have any built-in support for historical >> support >> > at this time, although we have thought for a long time that this >> > would be a great feature to have. >> > >> > You can, of course, do it yourself manually with a bunch of >> > persistent Date fields, but I agree that this is pretty >> cumbersome to >> > have to manage yourself. >> > >> > >> > >> > On May 18, 2007, at 11:27 AM, Ricardo Andere de Mello wrote: >> >>> > > Does OpenJPA have something similar to TopLink's "AsOfClause" ?>> > >>> > > I've been working for some time with OJB and Hibernate, and I'm>> > > work a lot >> > > with historical objects.>> > > It really sucks to manage lots of classes to build a historical>> > > structure of >> > > objects and object relations. >> > >>> > > Netminds beankeeper does a great job about this, but I'd like to>> > > adhere to >> > > JPA... >> > > >> > > Any idea of implementing historical objects AND RELATIONS, >> inside JPA? >> > > >> > > -- >> > > Ricardo Andere de Mello >> > > Presidente do Quilombo Digital >> > > 55 (11) 3271-7928 / 55 (11) 9917-7722 >> > >> > >> >> >> -- >> Ricardo Andere de Mello >> Presidente do Quilombo Digital >> 55 (11) 3271-7928 / 55 (11) 9917-7722 >>-- Ricardo Andere de Mello Presidente do Quilombo Digital 55 (11) 3271-7928 / 55 (11) 9917-7722
Craig Russell Architect, Sun Java Enterprise System http://java.sun.com/products/jdo 408 276-5638 mailto:[EMAIL PROTECTED] P.S. A good JDO? O, Gasp!
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