Help with mapping

_carl_ · **Posted:** Tue Jan 03, 2006 11:47 am

Hi,
I'm a beginner of NHibernate and need some help.
I have these database tables:

Nodes
---------
id:int
name:string

Connections
------------
scorecardId:int
nodeId:int

How would the xml look like if I want the class to look like this:

Node
-----------
ScorecardId:int
Children:IList
Name:string

Any help is appreciated!

/Carl

_carl_ · **Posted:** Tue Jan 03, 2006 11:51 am

Forgot one thing.. the Connections table should have a nodeIdParent.

benday · **Joined:** Tue Jan 03, 2006 4:42 pm **Posts:** 1

Hey _carl_,

If you want to model it with two tables, it'll look something like this

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
  <!-- MULTI TABLE IMPLEMENTATION -->
  <class name="Test.Node, Test" table="Nodes">
    <id name="NodeId" type="System.Int32" unsaved-value="0">
      <generator class="native" />
    </id>
    <property name="Name" not-null="true"></property>
    <bag name="Children" table="Connections" lazy="true" inverse="true" cascade="save-update">
      <key column="NodeIdParent"></key>
      <one-to-many class="Test.Node, Test" ></one-to-many>
    </bag>
  </class>
</hibernate-mapping>

You could also do it with just a single table and do it like this...

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
  <!-- SINGLE TABLE IMPLEMENTATION -->
  <class name="Test.Node, Test" table="Nodes">
    <id name="NodeId" type="System.Int32" unsaved-value="0">
      <generator class="native" />
    </id>
    <property name="Name" not-null="true"></property>
    <many-to-one name="Parent" column="NodeIdParent" not-null="false" cascade="save-update"></many-to-one>
    <bag name="Children" lazy="true" inverse="true" cascade="save-update">
      <key column="NodeIdParent"></key>
      <one-to-many class="Test.Node, Test" ></one-to-many>
    </bag>
  </class>
</hibernate-mapping>

DISCLAIMER: This isn't mapping isn't tested...so there may be some bugs.

-Ben

_carl_ wrote:

Hi,
I'm a beginner of NHibernate and need some help.
I have these database tables:

Nodes
---------
id:int
name:string

Connections
------------
scorecardId:int
nodeId:int

How would the xml look like if I want the class to look like this:

Node
-----------
ScorecardId:int
Children:IList
Name:string

Any help is appreciated!

/Carl

_carl_ · **Posted:** Wed Jan 04, 2006 4:27 am

Hi Ben and thanks for your answer!

I forgot one thing (again), the Connections table can contain several nodeId with the same value, but with different parents depending on in which scorecard they are in. So is there a way to have the class Node look something like this (pseudo):

Code:

<class name="Node" table="Connections">
 <id ... /> // as before
 <property name="Name" table="Nodes" />
 <property name="Scorecard" />
 <bag name="Children">
  <key column="NodeIdParent" />
  <one-to-many class="Node" />
 </bag>
</class>