0 Replies Latest reply on Sep 17, 2007 4:36 PM by Targo_06

    insert / delete problems using FDS with hibernate

    Targo_06
      Hi everyone,

      I'd be very thankful if anyone could help me with this problem because I got stuck on it for several weeks.

      I'm developing a FDS application with database connection and I've mapped a relational database to POJO's with Hibernate (using hibernate tools). I'm experiencing a lot of problems when I try to insert and delete items using the hibernate assembler. Here is my situation.

      My database, which represents information about cars, contains five tables:

      MODEL
      id
      engine
      transmission
      cab
      bed

      MODEL_PACK
      model_id
      pack_id
      inclusion_type

      PACK
      id
      name
      category

      MODEL_COLOR
      model_id
      color_id

      COLOR
      id
      extColor
      intColor

      The AS classes that represent this schema:

      Model.as

      id:int;
      engine:string;
      transmission:string;
      cab:string;
      bed:string;
      colors:ArrayCollection;
      packs:ArrayCollection;


      ModelPack.as

      id:ModelPackId;
      model:Model;
      pack:Pack;
      inclusion:String;

      ModelPackId is a custom class to store the composite primary key which is mapped to the corresponding java POJO.


      Pack.as

      id:String;
      category:String;
      name:String;
      models:ArrayCollection;


      Color.as

      id:String;
      extColor:String;
      intColor:String;
      models:ArrayCollection;



      The corresponding destinations in data-management-config.xml:

      <destination id="models.hibernate">
      ...........
      <many-to-many property="colors"
      destination="colors.hibernate" lazy="false"/>
      <one-to-many property="packs"
      destination="ModelsPacks.hibernate" lazy="true"/>
      ..............................


      <destination id="colors.hibernate">
      .............................
      <many-to-many property="models"
      destination="models.hibernate" lazy="true"/>
      ....................................


      <destination id="ModelsPacks.hibernate">
      ....................
      <identity property="id"
      type="com.fds.proyecto.hibernate.ModelPackId"/>
      <many-to-one property="model"
      destination="models.hibernate" lazy="true"/>
      <many-to-one property="pack"
      destination="packs.hibernate" lazy="true"/>
      ...................


      <destination id="packs.hibernate">
      ...................
      <one-to-many property="models"
      destination="ModelsPacks.hibernate" lazy="true"/>
      .....................


      As you can see the relationships are bidirectional.

      For example I have the data service to manage the operations in the front end and a datagrid:

      <mx:DataService id="models_ds" destination="models.hibernate" result="handleResult(event)"/>

      <mx:DataGrid id="modelList" dataProvider="{models_ac}"/>

      and a button:

      <mx:Button label="Delete" id="btnDelete" click="delModel()"/>

      The callback function only uses the hibernate assembler to delete the model:

      models_ds.deleteItem(modelList.selectedItem);
      models_ds.commit();

      It seems that the operation is performed succesfully but then when I check the database or reload the application the model that I've tried to delete is still there with its corresponding packs and colors. Sometimes the application throws a runtime error about synchronization. I've tried to remove the relations in the AS classes because I think that the problem have to do with the relations between classes and it works but in this case the application doesn't meet my requirements and the delete operation is more complex. Similar problems happen when I try to add Items.

      I've tried a lot of solutions to fix that problem (remove relations, convert them to unidirectional instead of bidirectional...) and I'd be deeply grateful if anyone can show me the procedure to add and delete items in that scenario. I've also thought that I could have missed any tag like "cascade" in the hibernate mapping files but I haven't tried this solution because I don't know what does it exactly mean.

      I have heard that the hibernate assembler has some bugs and in some circumstances it doesn't work properly. Could anyone confirm that?If true what should be the alternative solution? It's very important for me because this is a small part of my dissertation and I can't continue because I got stuck on this issue.

      Thanks a lot in advance,

      Carlos