persistence@glassfish.java.net

RE: question on entity relation. - unidirectional

From: Gordon Yorke <gordon.yorke_at_oracle.com>
Date: Tue, 11 Mar 2008 10:15:06 -0400

Hello Eve,
   I am not sure what you are asking with this email. What query are you talking about? The code attached is not setting stockinforent into iteamdetailsent and it is not persisting the iteamdetailsent entity either did you leave that part out? Can you explain what you want to have happen and what is happening now?
--Gordon
  -----Original Message-----
  From: Eve Pokua [mailto:gorgeous65_at_msn.com]
  Sent: Tuesday, March 11, 2008 9:34 AM
  To: persistence_at_glassfish.dev.java.net
  Cc: ejb_at_glassfish.dev.java.net
  Subject: RE: question on entity relation. - unidirectional


  Hello Gorgdon, everyone,
   
  Because Stockinforent is embedded within Iteamdetailsent both classes will be written to the same row in the same query.
  --Gordon

  Yes, I understood that and this is emphasised when I created the table.
  It is the query I am worried about. This is what I have done so far:
   
                   Departmentent departmentent =new Departmentent();
                   departmentent=em.find(Departmentent.class, departid);
                   Suppliercompanyent suppliercompanyent =new Suppliercompanyent();
                   suppliercompanyent=em.find(Suppliercompanyent.class, suppid);
                   DeliveryCompanyent deliveryCompanyent =new DeliveryCompanyent();
                   deliveryCompanyent=em.find(DeliveryCompanyent.class, delivid);
                   Stockinforent stockinforent;
    
                  String deliverydate="23/02/07"
                  long stockquanity=56;
    
                  Iteamdetailsent iteamdetailsent=new Iteamdetailsent(itmid,itmname, description, colour, price, itemsize, discount, departmentent);
                         
                 stockinforent=new(deliverydate,stockquanity, suppliercompanyent, deliveryCompanyent);
   
  Or I may replace the above with the set methods.
   
  Sorry, if I didn't make myself clear with my previous email
   
  Thanking you
   
  eve




----------------------------------------------------------------------------
    Date: Tue, 11 Mar 2008 08:53:49 -0400
    From: gordon.yorke_at_oracle.com
    To: persistence_at_glassfish.dev.java.net
    CC: ejb_at_glassfish.dev.java.net
    Subject: Re: question on entity relation. - unidirectional

    Because Stockinforent is embedded within Iteamdetailsent both classes will be written to the same row in the same query.
    --Gordon

    Eve Pokua wrote:
      Hello everyone,
       
      Regarding this Embeddable class:
       
      @Embeddable
      public class Stockinforent implements java.io.Serializable
      {
                                   @Column(name="DELIVERYDATE", nullable=false, length=35)
                                   private String deliverydate;
                                   @Column(name="STOCKQUAN", nullable=true, length=35)
                                   private Long stockquanity;
              
              
              
                                   @JoinColumn(name="sid")
                                   @ManyToOne
                                   private Suppliercompanyent suppliercompanyent;
               
                                   @JoinColumn(name="delivid")
                                   @ManyToOne
                                   private DeliveryCompanyent deliveryCompanyent;

      }

      The Stockinforent is an embeddable class inside Iteamdetailsent and it is also in relation to other entities as detailed above.
      To record a new record into the Iteamdetailsent table of the DB, I must have all and especially the ID of all relation entities.
      So how do I make sure both the new data for Iteamdetailsent and Stockinforent is entered into the DB at the same time( the data would
      be for the same record).
       
      Im a little stack in here so any suggestion would be apprecaited.
       
      Thanks
       
      eve


------------------------------------------------------------------------
        From: gorgeous65_at_msn.com
        To: persistence_at_glassfish.dev.java.net
        CC: ejb_at_glassfish.dev.java.net
        Date: Wed, 20 Feb 2008 21:55:57 +0000
        Subject: RE: question on entity relation. - unidirectional

        Hello everyone,
         
        James/Gordon,
         
        Thank you all so much for your help.
         
        So for anybody learning just like me, I used Embeddable for Stockinforent which was embedded within Iteamdetailsent with AttributeOverrides as:
         
        @Embedded
                @AttributeOverrides({
               @AttributeOverride(name="sid" , column=_at_Column(name="ssid")),
                @AttributeOverride(name="delivid" , column=_at_Column(name="sdelivid"))
                })
         
        And everything is working good.
         
        Thanks
         
        eve


----------------------------------------------------------------------
          From: gorgeous65_at_msn.com
          To: persistence_at_glassfish.dev.java.net
          CC: ejb_at_glassfish.dev.java.net
          Date: Wed, 20 Feb 2008 16:38:14 +0000
          Subject: RE: question on entity relation. - unidirectional

          Hello James/Gordon,
           
          First of all, I would like to say thank you so much for your replies.
           
          <
          Could you include your current mapping annotations or XML for the two
          classes.
>

           
          With regards to Stockinforent, this is how I relate to the other entities:

           
           
          public class Stockinforent implements java.io.Serializable
          {
              
          ......
                  @Id
                  @Column(name = "ITMID", insertable=false, updatable=false)
                  private String itmid;
                 @OneToOne()
                 @JoinColumn(name="ITMID")
                 private Iteamdetailsent iteamdetailsent;

                @JoinColumn(name="sid")
                @ManyToOne
                private Suppliercompanyent suppliercompanyent;
               @JoinColumn(name="delivid")
               @ManyToOne
               private DeliveryCompanyent deliveryCompanyent;
          ......
           
             public Iteamdetailsent getIteamdetailsent(){
                     return this.iteamdetailsent;}
           
             public void setIteamdetailsent(Iteamdetailsent iteamdetailsent){
                        this.iteamdetailsent=iteamdetailsent;
                       this.itmid = iteamdetailsent.getItmid();}

           public Suppliercompanyent getSuppliercompanyent(){
                  return this.suppliercompanyent;}
           
           public void setSuppliercompanyent(Suppliercompanyent suppliercompanyent){
                this.suppliercompanyent=suppliercompanyent;}
               
           public DeliveryCompanyent getDeliveryCompanyent(){
                return this.deliveryCompanyent;}
           
           public void setDeliveryCompanyent(DeliveryCompanyent deliveryCompanyent){
                this.deliveryCompanyent=deliveryCompanyent;}
           


          .......

          ...
          }
           
          How can I override entities as the get and set methods are of entity type
           If I understand what you mean:
           

 @Embedded
 @AttributeOverrides({
              @ManyToOne
       @AttributeOverride(name="sid" , column=_at_JoinColumn("ssid")),
     @AttributeOverride(name="delivid" , column=_at_JoinColumn("sdelivid"))})

:~) Or may be not?Thankseve
             

--------------------------------------------------------------------
            From: gordon.yorke_at_oracle.com
            To: persistence_at_glassfish.dev.java.net
            Date: Wed, 20 Feb 2008 11:00:28 -0500
            Subject: RE: question on entity relation. - unidirectional



            With regard to the exception, have you added the attribute overrides to the Entities that share the Stockinforent?
            --Gordon
              -----Original Message-----
              From: Eve Pokua [mailto:gorgeous65_at_msn.com]
              Sent: Wednesday, February 20, 2008 10:42 AM
              To: persistence_at_glassfish.dev.java.net
              Cc: ejb glassfish
              Subject: RE: question on entity relation. - unidirectional


              Hello,
               
              You are right and I've thought of that before. But all of my queries have a lot to
              do with Iteamdetailsent. And I have come so far with this project. Really, Stockinforent is actually part of Iteamdetailsent. I have divided it to give me a better control over the system. But may be
              I was wrong.
               
              eve






----------------------------------------------------------------
                Date: Wed, 20 Feb 2008 08:51:21 -0500
                From: gordon.yorke_at_oracle.com
                To: persistence_at_glassfish.dev.java.net
                CC: ejb_at_glassfish.dev.java.net
                Subject: Re: question on entity relation. - unidirectional

                Are you using Attribute overrides for the other class Suppliercompanyent?

                To solve your initial problem you could always query on the "Stockinforent" instead of "Iteamdetailsent" and use the OneToOne reference to display the "Iteamdetailsent" details.

                -- Gordon

                Eve Pokua wrote:

                  Hello everyone,
                   
                  I tried to used embeddable class as below but then got some error:
                   
                  Descriptor Exceptions:
                  ---------------------------------------------------------
                  Exception [TOPLINK-93] (Oracle TopLink Essentials - 2.0 (Build b58g-fcs (09/07/2007))): oracle.toplink.essentials.exceptions.DescriptorException
                  Exception Description: The table [ITEMS] is not present in this descriptor.
                  Descriptor: RelationalDescriptor(stockInformation.Suppliercompanyent --> [DatabaseTable(SUPPLIERS)])
                  Runtime Exceptions:
                  ---------------------------------------------------------
                  Deployment error:
                  The module has not been deployed.
                  See the server log for details.


                  The embeddable class is also in relation to another class. I'm kind of running out
                  of ideas and would appreciate any suggestions. Unless I have to stick to bidirectional.
                   
                  Thanks
                   
                  eve


------------------------------------------------------------
                    From: gorgeous65_at_msn.com
                    To: ejb_at_glassfish.dev.java.net
                    CC: persistence_at_glassfish.dev.java.net
                    Date: Mon, 18 Feb 2008 15:36:15 +0000
                    Subject: RE: question on entity relation. - unidirectional


                    Hello everyone,
                     
                    I was doing a research on this and came across the following about embeddable class:
                     
                    http://www.theserverside.com/tt/articles/article.tss?l=MigratingJDBC
                     
                    Check the entity Accounts and ContactInformation:
                     

@Entity
@Table(name = "ACT")
public class Account implements java.io.Serializable {

    protected String userId;
    protected ContactInformation info;
   
    public Account () {}
    
    public Account (String userId, ContactInformation info) {
        this.userId = userId;
        this.info = info;
    }

    @Id
    @Column(name="USERID")
    public String getUserId() {
        return userId;
    }
    @Embedded
    public ContactInformation getContactInformation() {
        return info;
    }
   
   
    
   ...
   ...

}_at_Embeddable
@Table(name = "ACT")

public class ContactInformation implements java.io.Serializable {

    protected String telephone;
    protected String email;
    protected String familyName;
    protected String givenName;
    
    public ContactInformation() {}

    public ContactInformation(String familyName,
                String givenName,
                String telephone,
                String email){

        this.givenName = givenName;
        this.familyName = familyName;
        this.email = email;
        this.telephone = telephone;
       }

    @Column(name="FIRSTNAME")
    public String getGivenName(){
        return givenName;
    }

   ...
   ...


}

                    The above code was copied from:
                     
                    http://www.theserverside.com/tt/articles/article.tss?l=MigratingJDBC
                     
                    Could this be the answer to my problems. Instead, have two entities and then one table. Embedded
                    one entity in another, so there is no worries of relations. Then in a case liken this, I would display data using
                    a code as below:
                     
                    acount.contactInformation.telephone;
                    acount.contactInformation.email;
                    acount.contactInformation.familyName;
                    acount.contactInformation.givenName;
                     
                    I'm I on the right track?
                     
                    Thanks
                     
                    eve
                     


                     


----------------------------------------------------------
                      From: gorgeous65_at_msn.com
                      To: ejb_at_glassfish.dev.java.net
                      CC: persistence_at_glassfish.dev.java.net
                      Date: Mon, 18 Feb 2008 13:16:11 +0000
                      Subject: question on entity relation. - unidirectional

                      hello everyone,
                       
                      I have two entities:
                       
                      public class Iteamdetailsent implements Serializable{
                       
                      @Id
                       @Column(name="ITMID", nullable=false, length=8)
                       private String itmid;
                       
                      ....
                       
                       
                      And
                       
                      public class Stockinforent implements java.io.Serializable
                      {
                              
                              @Id
                              @Column(name = "ITMID", insertable=false, updatable=false)
                              private String itmid;
                       @OneToOne()
                       @JoinColumn(name="ITMID")
                              private Iteamdetailsent iteamdetailsent;
                       
                      .....
                       
                      Stockinforent does not required an ID of it's own so it is using Iteamdetailsent foriegn key
                      as it's id. Now I am also using the MVC to get and display data to client. Moreover, I am
                      also using displaytag as part of my design. Now, I am using a servlet to retrieve data from the entities
                      and then forwarding data to a JSP to display to client. For example, in my display JSP:
                       
                       
                      <display:table name="sessionScope.iteamdetailsent" ..>
                       <display:column property="itmid" title=" Itemcode "/>
                              <display:column property="itmname" sortable="true" headerClass="sortable" title=" Name "/>
                       ...
                      </display:table>
                       
                       
                      Now, how do I display data or retrieve data of Stockinforent in relations to Iteamdetailsent?
                      I am hoping that I won't have to use bi-directional entity relation, as it's so hard to maintain.
                      Please, help.
                       
                       
                      Thanks
                       
                      eve
                       
                       
                       
                       


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