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Runtime Manipulation of <dynamic-component>

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tufelix

Post subject: Runtime Manipulation of <dynamic-component>

Posted: Tue Jun 12, 2007 5:38 am

Newbie

Joined: Tue Jun 12, 2007 5:22 am
Posts: 3

Hi!
Chapter 8.5 http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#components-dynamicin hibernate documentation about dynamic-component says:

Quote:

Runtime manipulation of the mapping document is also possible, using a DOM parser. Even better, you can access (and change) Hibernate's configuration-time metamodel via the Configuration object.

Is there an example or a more detailed explanation of the runtime manipulation?
How can i manipulate the Configuration object at runtime so that i can add a new column/property to a dynamic-component?

Hibernate version: 3.2.4 SP1

Mapping documents:
<hibernate-mapping>
<class name="sample.DynamicFieldCollection" table="DynamicFieldCollection">
<id name="id" column="Id" type="string">
<generator class="uuid.hex"/>
</id>
<one-to-one name="employee" class="sample.SampleEmployee"/>
<dynamic-component name="dynamicFields">
<property name="field_1" type="string" column="field_1"/>
</dynamic-component>
</class>

<class name="sample.SampleEmployee" table="Employee">
<id name="id" column="Id">
<generator class="uuid.hex"/>
</id>
<property name="title" column="Name"/>
</class>
</hibernate-mapping>

thomas

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GabrielSchmidt

Post subject:

Posted: Mon Jul 30, 2007 11:53 am

Newbie

Joined: Thu Jul 12, 2007 4:45 am
Posts: 6
Location: Germany

Good afternoon,

this was questioned several times but I can't find any answer, neither here nor in the entire internet. Is there any further documentation or example code available in the meantime?

I have understood from the former postings:

I can prepare a class for adding dynamic attributes by specifying an empty "dynamic component" section in my *.hbm.xml file...

Code:

  <class name="Northwind.Order, Northwind" table="OrderInformation">
   <id name="Id" type="Int32" column="Id">
      <generator class="assigned" />
   </id>

...

   <dynamic-component name="UserAttributes">
      </dynamic-component>
   </class>

...and implementing a map for mapping / accessing the dynamic attributes from my class (C# actually):

Code:

private System.Collections.IDictionary m_userAttributes;

public virtual System.Collections.IDictionary UserAttributes {
   get {
      return m_userAttributes;
   }
   set {
      m_userAttributes = value;
   }
}

Now what exactly do I have to do here...

Code:

Configuration cfg = new Configuration();
cfg.AddAssembly( "Northwind" );

// ???????????????????????????????

ISessionFactory factory = cfg.BuildSessionFactory();

...to map an additional column "FOOBAR" of type String to the class prepared with the map?

Best regards,

Gabriel Schmidt

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GabrielSchmidt

Post subject:

Posted: Fri Aug 10, 2007 5:07 am

Newbie

Joined: Thu Jul 12, 2007 4:45 am
Posts: 6
Location: Germany

Meanwhile I found some Java code fragments here. I tried to translate them to C#. My code now looks like this:

*.hbm.xml

Code:

<class name="Northwind.Order, Northwind" table="OrderInformation">
   <id name="Id" type="Int32" column="Id">
      <generator class="assigned" />
   </id>
   <dynamic-component name="UserAttributes">
   </dynamic-component>
</class>

*.cs

Code:

      private static Property addDynamicAttribute(
         String attributeName, String columnName, PersistentClass persistentClass ) {

         // Create a new db column specification.
         Column column = new Column( NHibernate.Type.TypeFactory.GetStringType( 100 ), 0 );
         column.Name = columnName;

         // Create a simple value that contains the column and will be set to the property as information.
         SimpleValue simpleValue = new SimpleValue( persistentClass.Table );
         simpleValue.AddColumn( column );
         simpleValue.Type = NHibernate.NHibernateUtil.String;

         // Create a new property.
         Property property = new Property();
         property.Name = attributeName;
         property.Value = simpleValue;

         return property;
      }

      static void Main( string[] args ) {
         try {
            Configuration cfg = new Configuration();
            cfg.AddAssembly( "Northwind" );
            PersistentClass pcOrder = cfg.GetClassMapping( typeof( Order ) );
            Property propUserAttributes = pcOrder.GetProperty( "UserAttributes" );
            Component compUserAttributes = ( Component )propUserAttributes.Value;
            compUserAttributes.AddProperty( 
               addDynamicAttribute( "myField1", "field_1", pcOrder ) );
            ISessionFactory factory = cfg.BuildSessionFactory();

The result of executing this code is an exception while building the session factory:

Code:

Aborting with exception:
NHibernate.MappingException: property mapping has wrong number of columns: Order
.Northwind.Order type: IDictionary
   at NHibernate.Mapping.PersistentClass.Validate(IMapping mapping)
   at NHibernate.Mapping.RootClass.Validate(IMapping mapping)
   at NHibernate.Cfg.Configuration.Validate()
   at NHibernate.Cfg.Configuration.BuildSessionFactory()
   at ORM.Center.Main(String[] args) in C:\Documents and Settings\workspace\Visual Studio 2005\Projects\ORM\Center.cs:line 70

Without calling "addDynamicAttribute" everything runs fine using the static mapping. Any ideas, please?

Best regards,

Gabriel Schmidt

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krishnajetti

Post subject: Re:

Posted: Thu Apr 15, 2010 2:34 pm

Newbie

Joined: Thu Apr 15, 2010 1:57 pm
Posts: 9

Hello Gabriel,
were you able to resolve this error? I am also stuck in the same situation.

Thanks

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