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From "Jeff Butler" <jeffgbut...@gmail.com>
Subject Re: Problem with several one to many relationships in breadth
Date Tue, 20 Feb 2007 17:10:59 GMT
Interesting....

In my tests, it fails in BOTH versions (2.1.7 and 2.3.0), but in different
ways.  So something definitely changed.  In my test, 2.3.0 is closer to
correct than 2.1.7 is.

But the important truth is that it does fail in both versions.

For now, I think a row handler is the best way to go forward with this.

I'll open a JIRA ticket with my test case, so everyone can see it.  No
guarantees about a fix, but at least it will be logged.

Jeff Butler



On 2/20/07, Jeff Butler <jeffgbutler@gmail.com> wrote:
>
> I''m surprised by this (obviously).  I'll take a look.  It probably has to
> do with the new support for multiple result sets.
>
> Jeff Butler
>
>
>
> On 2/20/07, Claudio Iacovozzi <claudio.iacovozzi@googlemail.com> wrote:
> >
> > I tested my given example with iBatis 2.1.7.597 and it works! Ibatis
> > creates the expected bean:
> > Agent1  --> List<Customer> {1:Customer1, 3:Customer2}
> >         --> List<Event> {1:housebreaking, 2:damage, 4:theft}
> >
> > Further tests with more depth (e.g. Custommer containing adresses) or
> > breadth (Agent containing additional List of addresses) were also
> > successful.
> >
> > So Tim ist right and something in iBatis must have been changed. We
> > currently use version 2.2.0.638 / 2.3.0.677.
> >
> > => so what's the best solution if we still want to use the newest
> > version? Should we implement our own row handler and how can that be done?
> > Or is it possible that the behaviour of 2.1.7.597 will be restored?
> >
> >
> >
> >
> >
> >
> >
> > 2007/2/19, Jeff Butler <jeffgbutler@gmail.com>:
> > >
> > > That's a good solution - then you could deal with object identity
> > > yourself.
> > >
> > > Jeff Butler
> > >
> > >
> > >  On 2/19/07, Larry Meadors <lmeadors@apache.org > wrote:
> > > >
> > > > ..or you could use a rowhandler.
> > > >
> > > > Larry
> > > >
> > > >
> > > > On 2/19/07, Jeff Butler <jeffgbutler@gmail.com > wrote:
> > > > >
> > > > > iBATIS groupBy support does not support two independant lists.
> > > > > This would be a very difficult problem to solve and would require
us to deal
> > > > > with object identity - which we don't deal with now.
> > > > >
> > > > > So with groupBy, you can have one and only one list that is
> > > > > automatically populated.  Other lists will need to be populated with
a
> > > > > nested select.
> > > > >
> > > > > Jeff Butler
> > > > >
> > > > >
> > > > >
> > > > > On 2/19/07, Tim.Hammar@mcnichols.com < Tim.Hammar@mcnichols.com
>
> > > > > wrote:
> > > > > >
> > > > > >
> > > > > > Greetings Claudio,
> > > > > >
> > > > > > We too have this problem with the latest two releases.  If you
> > > > > > use version 2.1.7.597 you should have no problems - hopefully
> > > > > > you have not implemented any new features like we had (and had
to scramble
> > > > > > to undo).  Versions 2.2 and 2.3 will not handle what you are
> > > > > > trying to do.  I have been so swamped that I have been unable
to generate a
> > > > > > test case and submit a bug report.  Maybe your example will
suffice.
> > > > > >
> > > > > > Regards,
> > > > > > Tim Hammar
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >   *"Claudio Iacovozzi" <claudio.iacovozzi@googlemail.com
>*
> > > > > >
> > > > > > 02/19/2007 06:51 AM   Please respond to
> > > > > > user-java@ibatis.apache.org
> > > > > >
> > > > > >    To
> > > > > > user-java@ibatis.apache.org  cc
> > > > > >
> > > > > >  Subject
> > > > > > Problem with several one to many relationships in breadth
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > We have a problem filling objects with several '1 to many
> > > > > > relationships' in breadth from one single SQL statement.
> > > > > >
> > > > > > On page 40 of the iBatis Data Mapper Developer Guide the
> > > > > > 'groupBy'
> > > > > > construct is described as follows:
> > > > > > "Using this approach, you can solve any N+1 problem of any depth
> > > > > > or breadth."
> > > > > >
> > > > > > This just seems to work for any depth but NOT for any *breadth*.
> > > > > >
> > > > > > Example:
> > > > > >
> > > > > > An insurance agent contains a list of customers as well as a
> > > > > > list of
> > > > > > insured events.
> > > > > >
> > > > > > <resultMap class="agent" id="agent" groupBy="id" >
> > > > > > <result property="id" column="agentId" />
> > > > > >  <result property="firstName" column="agent_firstname" />
> > > > > >  <result property="lastName" column="agent_lastname" />
> > > > > >  <result property="events" resultMap="event" />
> > > > > >  <result property="customers" resultMap="customer" />
> > > > > > </resultMap>
> > > > > >
> > > > > > <resultMap class="event" id="event" groupBy="id" >
> > > > > >  <result property="id" column="eventId" />
> > > > > >  <result property="title" column="title" />
> > > > > > </resultMap>
> > > > > >
> > > > > > <resultMap class="customer" id="customer" groupBy="id" >
> > > > > > <result property="id" column="customerId" />
> > > > > >  <result property="firstName" column="customer_firstname"
/>
> > > > > >  <result property="lastName" column="customer_lastname" />
> > > > > >  <result property="street" column="street" />
> > > > > >  <result property="city" column="city" />
> > > > > > </resultMap>
> > > > > >
> > > > > > - The used SQL statement:
> > > > > >
> > > > > > <select id="getAgent" resultMap="agent" parameterClass="int">
> > > > > > SELECT a.agentId, a.FirstName as agent_firstname, a.LastName
as
> > > > > > agent_lastname, b.eventId, b.title,
> > > > > > c.customerId, c.FirstName as customer_firstname, c.LastName
as
> > > > > > customer_lastname, c.street, c.city
> > > > > >
> > > > > > FROM insurance_agent a, agenteventlink ab, insured_event b,
> > > > > > customer c
> > > > > > WHERE a.agentId = ab.agentId
> > > > > > AND ab.eventId = b.eventId
> > > > > > AND b.customerId = c.customerId
> > > > > > AND a.agentId = #id#
> > > > > >
> > > > > > ORDER BY a.agentId,  c.customerId
> > > > > > </select>
> > > > > >
> > > > > > - The returned result set:
> > > > > > agentId,agent_firstname,agent_lastname,eventId,title,customerId,customer_firstname,customer_lastname
> > > > > >
> > > > > >
> > > > > > {1,Agent1,Smith,1,housebreaking,1,Customer1,Johnson}
> > > > > > {1,Agent1,Smith,4,theft,1,Customer1,Johnson}
> > > > > > {1,Agent1,Smith,2,damage,3,Customer2,Miller}
> > > > > >
> > > > > >
> > > > > > What we would like to achieve is getting a bean of type Agent,
> > > > > > which
> > > > > > contains two lists of all its customers and all its associated
> > > > > > insured events:
> > > > > >
> > > > > > Agent1  --> List<Customer> {1:Customer1, 3:Customer2}
> > > > > >             --> List<Event> {1:housebreaking, 2:damage,
4:theft}
> > > > > >
> > > > > >
> > > > > >
> > > > > > But iBatis creates a bean like this:
> > > > > > Agent1  --> List<Customer> {1: Customer1, 1:Customer1,
3:
> > > > > > Customer2}
> > > > > >            --> List<Event> {1:housebreaking, 2:damage,
4:theft}
> > > > > >
> > > > > >
> > > > > > We want to avoid several SQL statements to get the necessary
> > > > > > data (one
> > > > > > to get all events, and one to get all customers).
> > > > > >
> > > > > > Any solution ?
> > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

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