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From "William Shields" <william_shie...@jdv.com>
Subject RowHandler plus groupBy... bug?
Date Wed, 24 Oct 2007 01:48:06 GMT

Sorry, I sent this once but I wasn't subscribed so didn't know if I needed to send it again:

Perhaps foolishly I'm trying to combine the two.  I have a query that does a groupBy and works
well.  For arguments sake, let's call the master table Person and the detail record Album.
 A Person owns one or more Albums.  So:

public class Person {
  private int personId;
  private String name;
  private List<Album> albums;

public class Album {
  private int albumId;
  private String name;
  private int year;


resultMap id="album" class="Album">
  <result property="albumId" column="ALBUM_ID"/>
  <result property="name" column="ALBUM_NAME"/>
  <result property="year" column="YEAR"/>

<resultMap id="person" class="Person" groupBy="personId">
  <result property="personId" column="PERSON_ID"/>
  <result property="name" column="PERSON_NAME"/>
  <result property="albums" resultMap="album"/>

<select id="selectPersons" resultMap="person">
  SELECT person.person_id, person_name, album_id, album_name, year
  FROM person, album
  WHERE person.person_id = album.person_id

(ignoring the realities that it is better modeled as a M:N relationship)

If person A owns 8 albums, queryForList() works great.  However if you use a RowHandler for
this query, the size of the albums list is always 1.  Basically the RowHandler seems to be
getting called on the master object after a single row has been processed rather than when
a break occurs (and the list is full).  Am I right?  Or am I missing something?

Sounds like a bug to me.  I could ditch the groupBy and use the RowHandler only but I'm dealing
with a large result set and I'd otherwise have to build the complete object myself.  Unfortunately,
there doesn't seem to be a way to effectively delay processing until all list has been built.
 The RowHandler could use a lastValue property to manually calculate a break but that won't
get triggered after thelast row is processed (and a RowHandler doesn't know when something
is the last row).

Any suggestions?

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