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many-to-many mapping

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cagan327

Post subject: many-to-many mapping

Posted: Mon Jun 14, 2004 5:38 pm

Newbie

Joined: Mon Jun 14, 2004 5:16 pm
Posts: 16
Location: New York

Hi,
I'm quite new to Hibernate and am trying to modify my existing web apps' persistence layer to use it..

I have two database tables:

Code:

Portal (Portal_id, name, url, etc.)
Portal_Zipcode_Map (portal_id, zipcode)

There is no separate zipcode table, nor a zipcode_id field in Portal_zipcode_map....

Portal.java contains a

Code:

List postCodes

along with other properties.

PortalZipcodeMap.java has only:

Code:

Integer portalId
String zipcode

Both classes have their default constructors...

In Portal.hbm.xml I have defined the 'bag' as follows:

Code:

 <bag
            name="postCodes"
            table="portal_zipcode_map"
            lazy="false"
            inverse="true"
            cascade="none"
        >
     <key column="portal_id"/>
     <many-to-many  class=".PortalPostcodeMap"
                  column="postcode"
                  outer-join="false"/>

 </bag>

And this works...But I'm not confident that this is the best approach..

Do I have to represent the portal_postcode_map as a java class in order to populate the

Code:

postCodes

list of the

Code:

Portal

object?
Can't I simply load the postcodes as simple String values?

Thanks in advance.
Cagan

[/b]

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javamona

Post subject:

Posted: Mon Jun 14, 2004 5:53 pm

Beginner

Joined: Mon Sep 29, 2003 10:32 pm
Posts: 35
Location: Toronto, Ontario

Yes you can. See
http://www.hibernate.org/hib_docs/refer ... ns-mapping

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cagan327

Post subject: How to filter on a scalar collection element in select?

Posted: Wed Nov 10, 2004 12:22 pm

Newbie

Joined: Mon Jun 14, 2004 5:16 pm
Posts: 16
Location: New York

Hibernate Version: 2.1
Database: MySQL Standard 4.0.12

I have a Portal class that contains a set of Postcodes (String objects).

I created the following mapping in the Portal object for the postCodes set:

Code:

       
 <set
            name="postCodes"
            table="tbl_portal_postcode_map"
            lazy="true"
            inverse="false"
            cascade="none"
            sort="unsorted"
        >

              <key
                  column="portal_id"
              >
              </key>

              <element
                  column="postcode"
                  type="string"
                  not-null="false"
                  unique="false"
              />

        </set>

tbl_portal_postcode_map table contains two columns:

I'm trying to retrieve list Portal objects whose Postcode values match a certain value with the following Criteria:

Code:

 Criteria criteria = session.createCriteria(Portal.class);
 Criteria pCriteria = criteria.createCriteria("postCodes");
 pCriteria.add(Expression.ilike("postCodes.postcode", postcode + "%"));
 criteria.addOrder(Order.asc("name"));
            
  List results = criteria.list();

But I get the following exception:

Code:

WARNING: Unable to retrieve portals by postcode: collection was not an association: com.emirca.touch.module.share.model.portal.Portal.postCodes

How can I solve this?

Thanks in advance,
Cagan

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