[b]Hibernate version:[/b] 3.x

[b]Mapping documents:[/b]

<class name="us.tx.state.oag.WfPersonnelAction.HbmWfPaPersonnelActionTable"
table="info_wf_action">

<composite-id>
<!-- <key-property name="BatchId" column="batch_id" type="big_decimal"/> -->
<key-many-to-one name="BatchId" column="batch_id"/>
<key-property name="ActionId" column="action_id" type="big_decimal"/>
</composite-id>

<!--
<many-to-one name="BatchId" column="batch_id" cascade="all" not-null="true" update="false" insert="false"
class="us.tx.state.oag.WfPersonnelAction.HbmWfPaActionBatchTable"/>
-->
<many-to-one name="ActionTypeId" column="action_type_id" cascade="all" not-null="true" update="false" insert="false"
class="us.tx.state.oag.WfPersonnelAction.HbmWfPaCodeActionTypeTable"/>

<property name="CreatedWho" column="cr_who" type="string" update="true" insert="true"/>
<property name="CreatedWhen" column="cr_when" type="timestamp" update="true" insert="true"/>
<property name="UpdatedWho" column="up_who" type="string" update="true" insert="true"/>
<property name="UpdatedWhen" column="up_when" type="timestamp" update="true" insert="true"/>

</class>


Note the items that are commented out as opposed to active. The Active ones throw an error:

org.hibernate.MappingException: An association from the table info_wf_action refers to an unmapped class:
java.math.BigDecimal

Odd, since that's an internal data type.

We use natural keys almost exclusively. Just trying to figure out the best way to represent the relationships back to the parent tables. In this example, batch_id is the child here.

did you map BatchId as key-many-to-one instead of key-property intentionally or was that a mistake

That is my confusion. In this case, the info_wf_action table is a child to the info_wf_action_batch table; many-to-one in that same direction.

I'm sure there are multiple ways of doing this, but I'm trying to understand the key-many-to-one - what do I gain by using this syntax? (Beyond documentation in the xml file?) Is it better than the key-property and a follow up many-to-one?

Or is it just 6-of one and half-dozen of another?

Thanks!

You can have your mappings in the following way.





With the second mapping I removed key-many-to-one in composite-id and replaced it with key-property element. Also I have many-to-one element with insert="false" and update="false"

You can use either of <key-property> and <key-many-to-one> in your mappings. When you specify <key-many-to-one> you also need to specify the mapping class to which there is a relation defined. But if you want to get rid of <key-many-to-one> and use only <key-property> then the relation between the tables can be defined using <many-to-one> element using insert="false" and update="false" attributes. See this link for more information. http://www.hibernate.org/117.html#A34

duplicate post, hence contents deleted

The following seems to compile:

<class name="us.tx.state.oag.WfPersonnelAction.hbm.HbmWfPaSignaturesTable"
table="info_wf_action_signatures">

<composite-id>
<key-property name="BatchId" column="batch_id" type="big_decimal"/>
<key-property name="ActionId" column="action_id" type="big_decimal"/>
<key-property name="SignatureId" column="signature_id" type="big_decimal"/>
<key-property name="SignatureDate" column="signature_date" type="timestamp"/>
</composite-id>

<many-to-one name="BatchId" column="batch_id" cascade="all" not-null="true" update="false" insert="false"
class="us.tx.state.oag.WfPersonnelAction.hbm.HbmWfPaActionBatchTable"/>

<many-to-one name="ActionId" not-null="true" update="false" insert="false"
class="us.tx.state.oag.WfPersonnelAction.hbm.HbmWfPaPersonnelActionTable">
<column name="BatchId"/>
<column name="ActionId"/>
</many-to-one>

<many-to-one name="SignatureId" column="signature_id" cascade="all" not-null="true" update="false" insert="false"
class="us.tx.state.oag.WfPersonnelAction.hbm.HbmWfPaCodeActionSignaturesTable"/>

<!-- field definitions follow -->

But what I don't understand is why there is a name="" on the many-to-one; indeed w/o it the mapping is "invalid". As shown in the <composite-id> section, the primary key of my table is a quaternary one. I finally found the syntax for the many-to-one that can relate this class to the parent table with a primary key that is comprised of the first two fields. The third field of this table's PK is a single field FK to the signatures table. Ok. All's well.

Why do I need a name on the many-to-one and why does it have to be named after an existing field? "ID" doesn't work (as in composite-id) and missing isn't allowed.

This doesn't make sense to me.