multiple insert statement

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

i have 2 tables, thread and attachment. the structure of the tables are as follows:

thread
id (PK) auto-increment
msgText
submitDate
username

attachment
id(PK)
threadId (FK to thread 'id' column)
file
filename

I need to do my insert for these 2 tables. im stuck because i dont know how to insert into the 'attachment' table. The threadId is tagged to 'thread' id column. In hibernate how should i do it?

please advice. thanks.

batmat · **Posted:** Fri Mar 23, 2007 7:54 am

Well, just associate an attachment with a thread and you're done... Please show your javabeans and your mappings too.

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Hi fangEve,

it looks like it's a typical parent-child (one-to-many) relationship. To insert into both tables do the following:

1 / - Java code: add an instance of your Thread POJO class into
Attachment POJO class (with setter /getter )

2/ - Java code: add a Collection of Attachments into your Thread POJO (e.g. a Set)

3/ - add a convenience method to add an Attachment into a Thread (into your Thread POJO). E.g :

Code:

   public void addAttachment(Attachment at{
      at.setThread(this);
      if (attachments == null) {
         attachments = new HashSet();
      }
      attachments.add(at);
   }

4/ - Mapping: into your Thread.hbm.xml add the one-to-many relationship. E.g

Code:

      <set name="attachments" cascade="save-update">
         <key column="THREAD_ID" not-null="true"/>
         <one-to-many class="bla.bla.Attachment" />
      </set>

5/ - Mapping: into your Atachment.hbm.xml add the many-to-one relationship. E.g:

Code:

<many-to-one name="customer" foreign-key="CUSTOMER_ID" not-null="true"/>

6/ - Don't forget to use id generator class="native" for your 'auto_increment' stuff.

That should work fine.

Don't forget to rate

Chucky
----------------

thread
id (PK) auto-increment
msgText
submitDate
username

attachment
id(PK)
threadId (FK to thread 'id' column)
file
filename

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Sorry the last mapping (5/) in your Attachment.hbm.xml should be :

Code:

<many-to-one name="thread" foreign-key="THREAD_ID" not-null="true"/>

Don't forget to rate.
Chucky
--------

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

im having the following error:
org.hibernate.PropertyValueException: not-null property references a null or transient value: com..MessageAttachment.reply

what have i done wrongly? please advice, thanks.

Code:

[b]my mapping for attachment:[/b]
<hibernate-mapping>
    <class name="com.Attachment" table="ATTACHMENT">
        <id name="id" column="ID">
            <generator class="increment"/>
        </id>       
        <many-to-one name="reply" 
        class="com.thread" 
        foreign-key="THREAD_ID" not-null="true"/>
      <property name="filename" type="java.lang.String" column="FILENAME"/>
        <property name="file" type="binary" column="ATTACHMENT"/>        
           </class>       
</hibernate-mapping>

Code:

[b]my mapping for thread:[/b]
<hibernate-mapping>
    <class name="com.Reply" table="COLLAB_MESSAGE">
        <id name="id" column="ID">
            <generator class="increment"/>
        </id>       
       </many-to-one>
       <set name="file" cascade="save-update">
           <key column="MESSAGE_ID" not-null="false"/>
           <one-to-many class="com.MessageAttachment"/>
       </set>
        <property name="content" type="java.lang.String" column="MSG_TEXT"/> 
        <property name="submitUserId" type="java.lang.Integer" column="SUBMIT_USER_ID"/>     
        <property name="creationDate" type="java.util.Date" column="CREATED_DATE"/>
    </class>        
</hibernate-mapping>

Code:

[b]my java action class code:[/b]
MessageForm oForm =(MessageForm) form;
        Reply oReply= new Reply();
        Messenger msgr= new Messenger();
        MessageAttachment oMsgAttachment =  new MessageAttachment();
        oReply.setContent(oForm.getContent());
        oReply.setSubmitUserId(oForm.getSubmitUserId());
        oReply.setCreationDate(dtNowDate);
        oMsgAttachment.setFile(oForm.getFile().getFileData());
        oMsgAttachment.setFilename(oForm.getFile().getFileName());       
        msgr.addThreadMessage(oReply,oMsgAttachment);

batmat · **Posted:** Sun Mar 25, 2007 8:03 am

I guess you didn't provide all your mappings, namely the MessageAttachment one.

In this class, there seems to be a not-null relationship to Reply. I guess you didn't set it.

One other bizarre thing, you mapped a set to something named "file". Most of the time, collection mappings are plural.

Quote:

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

batmat wrote:

I guess you didn't provide all your mappings, namely the MessageAttachment one.

The MessageAttachment is actually mean Attachment. It's my typo

batmat wrote:

In this class, there seems to be a not-null relationship to Reply. I guess you didn't set it.

How do i do the mapping? can give an example? Im new to hibernate.

batmat wrote:

One other bizarre thing, you mapped a set to something named "file". Most of the time, collection mappings are plural.

Quote:

okie, noted. thanks. i will change it

thanks.

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Hi fangEve,

before saving your thread message, you must set the parent of the attachment (it's the thread that your saving). Because you specified the Attachment mapping that the parent (the Thread) is not null, so you must set it explicitly. I don't know how your "Messenger.addThreadMessage(oReply,oMsgAttachment);" looks like but you should have something like:

Code:

addThreadMessage(oReply,oMsgAttachment) {
  oMsgAttachment.setReply(oReply);
  ...
  session.saveOrUpdate(oReply);
}
 

chucky
-----------------------
Don't forget to rate

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

hi, chucky

thanks. i manage to get it work. but now i ned to select the records out. how am i going to do the query? i have no idea on how to query, to get the child and parent

thanks.

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Hi fangEve,
you have different possibilities to make queries:
1/ - via Criteria:

Code:

  Criteria criteria = session.createCriteria(YourThread.class);
  List threads = criteria.list(); // you get a list of your Thread
  for (int i = 0; i < threads.size(); i++) {
      YourThread t = (YourThread)threads.get(i); // you get a thread
      Set attachments = t.getAttachments(); // you get the associated attachments 
  }

2/ - via HQL:

Code:

  Query q = session.createQuery("from bla.bla.YourThread");
  List threads = q.list(); // you get a list of your Thread
  for (int i = 0; i < threads.size(); i++) {
      YourThread t = (YourThread)threads.get(i); // you get a thread
      Set attachments = t.getAttachments(); // you get the associated attachments 
  }

3/- via native SQL (check the hibernate documention)

Chucky - DON'T FORGET TO RATE if that helps...

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

i have another problem, is related to the 2 tables asked previously.

thread
id (PK) auto-increment
msgText
submitDate
userid

user
id
userid
username

admin
id
userid username

i need to retrieve the username from either user or admin table. In the thread table, the userid, will appear either in user of the admin table. so how do i do the query?

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Hi fangEve,
your table structure is not clear. userId refers to what? The id of the User table? If yes, why does the User table have id AND userId columns?

fangEve · **Joined:** Sat Mar 03, 2007 5:32 am **Posts:** 20

[quote="chucky"]2/ - via HQL:

Code:

  Query q = session.createQuery("from bla.bla.YourThread");
  List threads = q.list(); // you get a list of your Thread
  for (int i = 0; i < threads.size(); i++) {
      YourThread t = (YourThread)threads.get(i); // you get a thread
      Set attachments = t.getAttachments(); // you get the associated attachments 
  }

[quote]

how am i going to dislay the attachments? im using struts. I need to display the attachment id, and filename. thanks

chucky · **Joined:** Mon Jun 12, 2006 5:33 am **Posts:** 63

Hi fangEve,

Once you get your Set of attachments, all you need is to iterate through it.
You get each time an Attachment object, then you retrieve the properties you need:
So to continue the example:

Code:

  Query q = session.createQuery("from bla.bla.YourThread");
  List threads = q.list(); // you get a list of your Thread
  for (int i = 0; i < threads.size(); i++) {
      YourThread t = (YourThread)threads.get(i); // you get a thread
      Set attachments = t.getAttachments(); // you get the associated attachments
      
[b]      Iterator it = attachments.iterator();
      while (it.hasNext()) {
         Attachment at = (Attachment) it.next();
         long id = at.getId();
         String fn = at.getFileName();
         ...

      }[/b]
      
  }

With Struts, you could use the <logic:iterate> tag to iterate through your Set of attachments.
see Struts documentation to see how to use it:
http://struts.apache.org/1.3.8/struts-t ... ml#iterate

gubrak · **Joined:** Tue Mar 20, 2007 5:13 am **Posts:** 9

1 question related to this issue ....

if you have a set <one-to-many> at parent's table
and <many-to-one> at child's table.

If you want to set a new parent for a child ... do u need to...
a

Code:

child.setParent(newParent);

or

b

Code:

Parent oldParent = child.getParent();
oldParent.removeChild(child);
newParent.addChild(child);
child.setParent(newParent);

in summary ... do u need to set each parent and child manually or hibernate would taking care of it??

This is if cascade="all"