Thank you for the hint, Ryan.
I tried using the subselect, and it works. However, the way I made it
work seems awkward, I think I did not fully understand your proposal.
What I managed to do is this:
I made a result map for the base class:
<resultMap id="eventsMap" class="EventBaseClass">
.....
<discriminator javaType="string" column="type"
jdbcType="VARCHAR">
<subMap value="UserLoggedIn"
resultMap="userLoggedInMap"></subMap>
</discriminator>
</resultMap>
and here's the submap for a concrete event type:
<resultMap id="userLoggedInMap" class="UserLoggedInEvent"
extends="eventsMap">
<result property="remoteAdress" select="fetchRemoteAddr"
column="eventid"/>
<result property="userAgent" select="fetchUserAgent"
column="eventId"/>
</resultMap>
The select queries are all analogous, they look like this:
<select id="fetchRemoteAddr" parameterClass="int" resultClass="string">
select ip from eventuserloggedin where eventid=#value#
</select>
What I would like to do is, like you described, to have the subselect
add the parameters to the result map in one shot... Am I on the right
track or did I miss it completely? Sorry for being slow off the mark...
On Mar 13, 2008, at 7:50 PM, Ryan Shelley wrote:
Could you use a nested select? Check out page 34, under "Complex
Properties":
http://ibatis.apache.org/docs/java/pdf/iBATIS-SqlMaps-2_en.pdf
The idea is that one ResultMap contains a complex type that consists
of the results from another select. So if tableA has a primary key,
and tableB has a foreign key to the primary key in tableA, you'd
have a ResultMap of tableA results, and in each result from tableA
exists a List (or Object) of ResultMap(s) that match the foreign key
in tableB. One iBATIS query would execute the primary select to
gather tableA results, and then automatically, a separate select
will execute to gather the results for each tableA result and insert
them into tableA's ResultMap.
I might be incorrect, but I think the docs might be wrong. It says:
<result property="category" column="PRD_CAT_ID" select="getCategory"/>
and it should be:
<result property="category" column="PRD_ID" select="getCategory"/>
because you want to map PRD_ID from PRODUCT into the getCategory
select.
-Ryan
On Thu, Mar 13, 2008 at 2:54 AM, Eric Andres <[EMAIL PROTECTED]>
wrote:
Hello,
I have a problem writing a polymorphic query. As I am new to iBatis, I
started digging the list archive and stumbled upon the discriminator
and submap tags, and I also found this in the archives:
http://www.mail-archive.com/[email protected]/msg00070.html
, my situation is pretty close to Niels', but there was no solution in
that thread...
The situation I'm in is this: I have a type hierarchy representing
events consisting of a base class (call it Event) and a subclass for
each event type (30+ currently). It's representation in the database
was done with a table-per-subclass strategy.
I want to write a query that fetches an event based on it's ID. The
problem is that I don't know the event type I'm going to fetch in
advance, and I want to avoid a 30-table join. Is there a way a
delaying the join to a second query after the 'discrimination'?
Something like
<resultMap id="Event" class="BaseEvent">
...
<result property="ts" column="timestamp/>
<discriminator javaType="string" column="type">
<subMap value="userLoggedIn"
select="addUserLoggedInProps"/>
...
</discriminator>
</resultMap>
...
<select id="addUserLoggedInProps" parameterClass="int"
resultMap="userLoggedInEvent">
select * from event, userloggedinevent
where event.id=userloggedin.eventid and event.id=#value#
</select>
...
<resultMap id="userLoggedInEvent" extends="Event">
...
<result property="userId" column="userid"/> <!-- specific to
userLoggedInEvent -->
...
</resultMap>
Sorry for the lengthy post. Any help greatly appreciated...
Thanks for your time,
Eric
