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From Nathan Maves <Nathan.Ma...@Sun.COM>
Subject Re: N+1 with a twist?
Date Thu, 10 Feb 2005 23:02:42 GMT
That is how I was going to handle them.  I was just looking to see if 
there was some tricky way  to use "select *" from multiple tables.  I 
have one table that has 30 columns in it.  It is very painful to list 
out each column :)

Nathan
On Feb 10, 2005, at 3:50 PM, Kris A. Jenkins wrote:

> Nathan,
>
> Ambiguous column names are easily handled.  Just
> differentiate the names in the query, then you can
> assign them explicitly in the resultMaps.  Here's an
> example with an ambiguous 'name' column:
>
> <sqlMap namespace="Example">
>  <resultMap id="parentResult" class="com.eg.Parent"
> groupBy="parentId">
>   <result property="parentId" column="parent_id"/>
>   <result property="name" column="parent_name"/>
>   <result property="children"
> resultMap="Example.childResult"/>
>  </resultMap>
>
>  <resultMap id="childResult" class="com.eg.Child">
>   <result property="name" column="child_name"/>
>   <result property="description"
> column="description"/>
> column="broadcastEndDate"/>
>  </resultMap>
>
>  <select id="getFamilies" resultMap="parentResult">
>   select
>     p.id AS parent_id,
>     p.name AS parent_name,
>     c.name AS child_name,
>     c.desc AS description
>   FROM child c, parent p
>   WHERE p.id = c.parent_id
> </select>
> </sqlMap>
>
> In this example both the column and the property names
> are ambiguous, but it's gracefully handled. :-)
>
> HTH,
> Kris
>
>  --- Nathan Maves <Nathan.Maves@Sun.COM> wrote:
>> Great!  I will give it a try.
>>
>> What do you suggest when you have ambiguously
>> defined column names in a
>> n+1 query?
>>
>> nathan
>> On Feb 9, 2005, at 10:30 AM, Clinton Begin wrote:
>>
>>> If you can join the data into a single resultset
>> with repeating
>>> groups, the N+1 solution will work, no matter how
>> the collections are
>>> arranged.
>>>
>>> As long as you group by some column in table_a,
>> you can separately map
>>> 2 collections on the same class.
>>>
>>> This will work.
>>>
>>> Try it out!
>>>
>>> Clinton
>>>
>>> On Wed, 09 Feb 2005 10:21:54 -0700, Nathan Maves
>>> <Nathan.Maves@sun.com> wrote:
>>>> I dont think that the current implementation will
>> work for this but I
>>>> was looking for some best practices on how to do
>> it.
>>>>
>>>> Parent Class A has n number of List properties
>> that all come for their
>>>> own tables.
>>>>
>>>> A from table_a
>>>>         List of B from table_b
>>>>         List of C from table_c
>>>>         .
>>>>         .
>>>>         .
>>>>
>>>>
>>>> Nathan
>>>>
>>>>
>>
>>
>
>
> 	
> 	
> 		
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