Re: How to handle inserts/update for collections and associations

[Jeff Butler]

This is true.  MyBatis does not keep track of the state of your objects - you have to do that yourself.

I usually end up writing a service object that does the work.  The service object interacts with the mappers for each individual object.  For me, there's usually a loop that looks like this:

for each child object

   update child object

   if (rows updated == 0)

      insert child object

   end if

end for

If you allow deletes, then the loop might look like this:

delete all children

for each child object

   insert child object

end for

Alternatively you could try to implement some kind of strategy to determine if the object has changed - maybe set a "dirty flag" with each setter.  I'll say that every time I've tried to go down that path I've ended up regretting it.  This is, essentially, what Hibernate does.  They do it in a systematic way that is less error prone than trying to write it yourself.

Jeff Butler

On Wed, Aug 22, 2012 at 4:10 PM, rogergl <ro...@gilliar.de> wrote:

Hi,

I just started to use myBatis (after using Hibernate now for some years) and I really like the way to map even complex queries. But now I'm wondering how I would implement inserts/update of an object containing collections and 
associations.

Example:

<resultMap id="resultMap" type="de.test.Vkprlist">

    <result property="id" column="v_id" />

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

    <collection property="preise" ofType="de.test.Vkpreise">

        <result property="id" column="p_id" />

        <result property="pzn" column="p_pzn"/>

        <association property="artikel"  resultMap="artikelResult" />

     </collection>

</resultMap>

It seems as If I have to check what objects from the collections must be inserted or updated (maybe by checking if the id is set ?). This would require one insert/update statement for the collection, one insert/update statement for the association and one insert/update for the main object. 

Is that true ?

Regards

  Roger

[rogergl]

Hi,

thanks for your answer. I'm glad it is working as I expected it to work ;-)

Regards

  Roger