Succinctest way of using Complex Collection Properties ?

[fxbird]

Hi, all:

 

   what's the Succinctest way of using Complex Collection Properties ? 

 

   As we know ,when we do a 1:1 query , a bean has a complex bean property for instance a Product has a Category property, we can write the select statement query a product and its category like below:

 

    <select id="getProductWithCategory"  resultClass="product"  parameterClass="int">

        select

           p.prd_id pid,

           p.prd_name name,

           p.prd_description description,

           c.cat_id as "category.cid",

           c.cat_name as "category.name"

        from product p,category c

         where p.prd_id=#pid# and p.cat_id=c.cat_id

    </select>

 

    that is , we don't need do as guide doc says, define two resultMap for that, just use dot referring to the relationship. How succinct , graceful it is!  But how about Complex Collection Properties  , how about a Category has a list property referring to all the products related?

    To query a category and its product list , I have to do fully according to what guide says,define two resultMap as below, it does work, but a little boring. Is there better , succint way to it?

 

 <typeAlias alias="product" type="xdg.model.Product"/>

    <typeAlias alias="category" type="xdg.model.Category"/>

   <resultMap id="productList" class="product">

       <result property="pid" column="prd_id"/>

       <result property="name" column="prd_name"/>

   </resultMap>

   <resultMap id="categoryResult" class="category" groupBy="cid">

       <result property="cid" column="cat_id"/>

       <result property="name"  column="cat_name"/>

       <result property="products" resultMap="category.productList"/>

   </resultMap>

    <select  id="getCategoryList" resultClass="category">

        select *  

        from category c,product p

        where c.cat_id=p.cat_id

        order by c.cat_id;

    </select>

 

 

  thank so much.

 

Kurt

2010-08-14

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fxbird

[Poitras Christian]

From what I see you are using iBATIS 2. In this case I think it is the way to go.

In MyBatis 3, you can nest a resultMap inside a <collection> element.

 

Christian

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From: mybati...@googlegroups.com [mailto:mybati...@googlegroups.com] On Behalf Of fxbird
Sent: Saturday, August 14, 2010 9:18 AM
To: mybatis-user
Subject: Succinctest way of using Complex Collection Properties ?

[fx bird]

Hi Christian:

   You mean it's only way in ibatis2?

    thanks.

Kurt

[Poitras Christian]

I am sorry, I don't really use iBATIS 2 anymore.

 

After a quick look, you can use groupBy in your resultMap.

   <resultMap id="categoryResult" class="category" groupBy="cid">

       <result property="cid" column="cat_id"/>

       <result property="name"  column="cat_name"/>

       <result property="products.pid" column="prd_id"/>

       <result property="products.name" column="prd_name"/>

   </resultMap>

 

Christian

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From: mybati...@googlegroups.com [mailto:mybati...@googlegroups.com] On Behalf Of fx bird

Sent: Monday, August 16, 2010 10:47 AM
To: mybati...@googlegroups.com
Subject: Re: Succinctest way of using Complex Collection Properties ?