Re: How to persist an entity when its within a collection of another entity

Cheers Greg I will check nhibernate out as well.

--- In domaindrivendesign <at> yahoogroups.com, "Greg Young" 
<gregoryyoung1@...> wrote:
>
> That will work fine ... you can use the linq objects as DAOs. You 
may
> however want to at least research nhibernate as it supports many 
more
> complex mappings (many even use nhibernate straight into their
> domain). Personally I am not a fan of an OR mapper going directly to
> domain objects (mainly because persistence ignorance is still
> non-existent with any product I have used) but many have done so and
> been very effective.
> 
> Cheers,
> 
> Greg
> 
> On Sun, Aug 3, 2008 at 1:30 PM, Scott Millett <scott@...> wrote:
> > Yes I was going to look at Linq as an O/R Mapper. I was thinking 
of
> > using it to generate objects that are basically tables and then 
have
> > another layer to turn these into my complex domain objects. Do you
> > think that this is a good idea?
> >
> > --- In domaindrivendesign <at> yahoogroups.com, "Greg Young"
> > <gregoryyoung1@> wrote:
> >>
> >> Yes AOP can be used here ... You might want to look at one of the
> >> numerous dynamic proxy generators as a method of handling this
> > (again
> >> this is what many OR mappers already do). Just one point though, 
if
> >> you are doing all this work might it be easier to just leverage 
all
> >> the work people have already done on this and just use something
> > like
> >> linq2sql or nhibernate?
> >>
> >> Cheers,
> >>
> >> Greg
> >>
> >> On Sun, Aug 3, 2008 at 1:04 PM, Scott Millett <scott@> wrote:
> >> > Thanks Greg,
> >> >
> >> > I think I will go for option 1, I was hesitant about doing this
> >> > because I wasn't sure that my entity would still be focused on 
the
> >> > business concern. Is this what they call a Domain Model Anti-
> > Pattern?
> >> >
> >> > I have found a great article about this here
> >> > http://www.infoq.com/articles/aspects-of-domain-model-mgmt.
> >> >
> >> > --- In domaindrivendesign <at> yahoogroups.com, "Greg Young"
> >> >
> >> > <gregoryyoung1@> wrote:
> >> >>
> >> >> Shouldn't CustomerService be CustomerRepository here?
> >> >>
> >> >> It sounds like Customer is your aggregate root which means 
that
> > yes
> >> >> you should be able to say Model.CustomerRepository.Save
(customer)
> >> > and
> >> >> it should handle all changes that belong to the customer
> > aggregate.
> >> >> You mentioned that you are not using an OR mapper, as such you
> > would
> >> >> have to introduce some of this code yourself.
> >> >>
> >> >> The general method of doing this is either:
> >> >> 1) Track changes that occur to your domain object with things
> > like
> >> >> dirty flags/version numbers
> >> >> 2) Keep 2 copies of the graph (one as you loaded it one that 
you
> >> > give
> >> >> back to the caller) then walk the graph when save is called 
and
> >> >> compare the two graphs looking for any changes.
> >> >>
> >> >> These are the two most common ways that OR mappers handle this
> >> > problem
> >> >>
> >> >> Cheers,
> >> >>
> >> >> Greg
> >> >>
> >> >> On Sun, Aug 3, 2008 at 9:25 AM, Scott Millett <scott@> wrote:
> >> >> > I have a Customer entity and a Customer has an address book
> > which
> >> > is a
> >> >> > collection of address entities. When I save a customer I 
don't
> >> > really want
> >> >> > to be looping through each of his addresses and persisting 
it
> > to
> >> > my
> >> >> > database. To save a customer I use this code:~
> >> >> >
> >> >> > Dim
> >> >> >
> >> >> > aCustomer As Model.Customer
> >> >> >
> >> >> > aCustomer = Model.CustomerService.getCustomer(CustomerID)
> >> >> >
> >> >> > Model.CustomerService.SaveCustomer(aCustomer)
> >> >> >
> >> >> > That all works fine and makes sense. Now if I wanted to Add,
> > Edit
> >> > or Remove
> >> >> > a Customers Address I would use the code:
> >> >> >
> >> >> > Dim aCustomer As Model.Customer
> >> >> >
> >> >> > aCustomer = Model.CustomerService.getCustomer(CustomerID)
> >> >> >
> >> >> > aCustomer.AddressBook(1).PostCode = "PO5 3ED"
> >> >> >
> >> >> > Model.CustomerService.SaveCustomerAddress
(aCustomer.AddressBook
> >> > (1))
> >> >> >
> >> >> > If this acceptable or should I be able to call simply
> >> >> >
> >> >> > Model.CustomerService.SaveCustomer(aCustomer)And have it
> > persist
> >> > any changes
> >> >> > that have been made to the customers address book? And how
> > would
> >> > I be able
> >> >> > to save any changes without having to loop through the 
entire
> >> > collection and
> >> >> > saving each one individually. I am not using any O/R mapping
> >> > tools.
> >> >> >
> >> >> > Thanks for your help.
> >> >> > Scott
> >> >> >
> >> >> >
> >> >> >
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> It is the mark of an educated mind to be able to entertain a
> > thought
> >> >> without accepting it.
> >> >>
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> It is the mark of an educated mind to be able to entertain a 
thought
> >> without accepting it.
> >>
> >
> > 
> 
> 
> 
> -- 
> It is the mark of an educated mind to be able to entertain a thought
> without accepting it.
>

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