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Posted to user-java@ibatis.apache.org by Dan Bradley <de...@gmail.com> on 2005/09/19 21:15:30 UTC
Mapping Composition (aka composite property, aka value objects)
I have one entity, a Product, which holds a Price as a composed (not
related) entity. A Price is a numeric value and a currency code as a
String. Prices don't have a distinct identity in the database - they
are value objects, so this is not the more usual persistent entity to
persistent entity relationship mapping.
How would you map this using iBATIS? I've tried a variety of things
without success and can't yet find any documentation that covers this
situation. Thanks.
Re: Mapping Composition (aka composite property, aka value objects)
Posted by Dan Bradley <de...@gmail.com>.
I have the same question myself, but haven't yet figured out how to
handle that situation.
Anyone else know?
On 9/20/05, Volker_Reichel@t-online.de <vo...@t-online.de> wrote:
> If iBATIS is doing these steps
>
> Product product = new Product();
> product.getPrice().setAmount(amount);
>
> the Product constructor has to create a Price instance as side-effect.
> My question is: What do you do in case the Product does not need to have a
> related Price instance for each Product?
>
>
> Volker
>
> -----Ursprüngliche Nachricht-----
> Von: Dan Bradley [mailto:debradley@gmail.com]
> Gesendet: Montag, 19. September 2005 22:11
> An: lmeadors@apache.org
> Cc: user-java@ibatis.apache.org
> Betreff: Re: Mapping Composition (aka composite property, aka value
> objects)
>
>
> Of course, after being stuck on it for a while, I figured it out right
> after I posted the question:
>
> <typeAlias alias="product" type="com.foo.Product" />
> <resultMap id="result" class="product">
> <result property="name" column="name" />
> <result property="description" column="description" />
> <result property="price.amount" column="amount" />
> <result property="price.currency" column="currency_code" />
> </resultMap>
>
> It appears that the Product class must have a Price instance that is
> initialized, not null. In other words it looks like iBATIS doesn't do:
>
> Price price = new Price();
> price.setAmount(amount);
> Product product = new Product();
> product.setPrice(price);
>
> But instead does:
>
> Product product = new Product();
> product.getPrice().setAmount(amount);
>
> Take this all with a grain of salt - I'm new to iBATIS!
>
> On 9/19/05, Larry Meadors <la...@gmail.com> wrote:
> > Can you explain more how the model is in Java, and in the database?
> >
> > Larry
> >
> >
> > On 9/19/05, Dan Bradley <de...@gmail.com> wrote:
> > > I have one entity, a Product, which holds a Price as a composed (not
> > > related) entity. A Price is a numeric value and a currency code as a
> > > String. Prices don't have a distinct identity in the database - they
> > > are value objects, so this is not the more usual persistent entity to
> > > persistent entity relationship mapping.
> > >
> > > How would you map this using iBATIS? I've tried a variety of things
> > > without success and can't yet find any documentation that covers this
> > > situation. Thanks.
> >
>
>
AW: Mapping Composition (aka composite property, aka value objects)
Posted by "Volker_Reichel@t-online.de" <vo...@t-online.de>.
If iBATIS is doing these steps
Product product = new Product();
product.getPrice().setAmount(amount);
the Product constructor has to create a Price instance as side-effect.
My question is: What do you do in case the Product does not need to have a
related Price instance for each Product?
Volker
-----Ursprüngliche Nachricht-----
Von: Dan Bradley [mailto:debradley@gmail.com]
Gesendet: Montag, 19. September 2005 22:11
An: lmeadors@apache.org
Cc: user-java@ibatis.apache.org
Betreff: Re: Mapping Composition (aka composite property, aka value
objects)
Of course, after being stuck on it for a while, I figured it out right
after I posted the question:
<typeAlias alias="product" type="com.foo.Product" />
<resultMap id="result" class="product">
<result property="name" column="name" />
<result property="description" column="description" />
<result property="price.amount" column="amount" />
<result property="price.currency" column="currency_code" />
</resultMap>
It appears that the Product class must have a Price instance that is
initialized, not null. In other words it looks like iBATIS doesn't do:
Price price = new Price();
price.setAmount(amount);
Product product = new Product();
product.setPrice(price);
But instead does:
Product product = new Product();
product.getPrice().setAmount(amount);
Take this all with a grain of salt - I'm new to iBATIS!
On 9/19/05, Larry Meadors <la...@gmail.com> wrote:
> Can you explain more how the model is in Java, and in the database?
>
> Larry
>
>
> On 9/19/05, Dan Bradley <de...@gmail.com> wrote:
> > I have one entity, a Product, which holds a Price as a composed (not
> > related) entity. A Price is a numeric value and a currency code as a
> > String. Prices don't have a distinct identity in the database - they
> > are value objects, so this is not the more usual persistent entity to
> > persistent entity relationship mapping.
> >
> > How would you map this using iBATIS? I've tried a variety of things
> > without success and can't yet find any documentation that covers this
> > situation. Thanks.
>
Re: Mapping Composition (aka composite property, aka value objects)
Posted by Dan Bradley <de...@gmail.com>.
Of course, after being stuck on it for a while, I figured it out right
after I posted the question:
<typeAlias alias="product" type="com.foo.Product" />
<resultMap id="result" class="product">
<result property="name" column="name" />
<result property="description" column="description" />
<result property="price.amount" column="amount" />
<result property="price.currency" column="currency_code" />
</resultMap>
It appears that the Product class must have a Price instance that is
initialized, not null. In other words it looks like iBATIS doesn't do:
Price price = new Price();
price.setAmount(amount);
Product product = new Product();
product.setPrice(price);
But instead does:
Product product = new Product();
product.getPrice().setAmount(amount);
Take this all with a grain of salt - I'm new to iBATIS!
On 9/19/05, Larry Meadors <la...@gmail.com> wrote:
> Can you explain more how the model is in Java, and in the database?
>
> Larry
>
>
> On 9/19/05, Dan Bradley <de...@gmail.com> wrote:
> > I have one entity, a Product, which holds a Price as a composed (not
> > related) entity. A Price is a numeric value and a currency code as a
> > String. Prices don't have a distinct identity in the database - they
> > are value objects, so this is not the more usual persistent entity to
> > persistent entity relationship mapping.
> >
> > How would you map this using iBATIS? I've tried a variety of things
> > without success and can't yet find any documentation that covers this
> > situation. Thanks.
>
Re: Mapping Composition (aka composite property, aka value objects)
Posted by Larry Meadors <la...@gmail.com>.
Can you explain more how the model is in Java, and in the database?
Larry
On 9/19/05, Dan Bradley <de...@gmail.com> wrote:
> I have one entity, a Product, which holds a Price as a composed (not
> related) entity. A Price is a numeric value and a currency code as a
> String. Prices don't have a distinct identity in the database - they
> are value objects, so this is not the more usual persistent entity to
> persistent entity relationship mapping.
>
> How would you map this using iBATIS? I've tried a variety of things
> without success and can't yet find any documentation that covers this
> situation. Thanks.