HELP! HELP! URGENT!How to query a composite key class

dika151 · **Joined:** Thu Jul 21, 2005 10:25 pm **Posts:** 4

I'm using myeclipse to develop my system.

I have a table named Tapplicationproject in my database.

When I generated the hibernate mapping using myeclipse, The following files were created:

- AbstractTapplicationproject.java
properties that I need (all are accessible from Tapplicationproject.java):
- description
- endDate
- id
- location
- role
- startDate
- tools

- Tapplicationproject.java
properties that I need: (NONE) but I'm using this class to access all fields because this is the child class of AbstractTapplicationproject.java

- TapplicationprojectKey.java
properties that I DESPERATELY need:
- applicationId
- projectName

- Tapplicationproject.hbm.xml

Now, I need to get ALL fields from Tapplicationproject table.

The problem is, the composite primary keys ('applicationId' & 'projectName' properties) are stored ONLY in the TapplicationprojectKey.java and I cannot query this class.

When I tried to query TapplicationprojectKey.java, the compiler said that TapplicationprojectKey is not a persistent class. So I have no idea how to query the 'applicationId' & 'projectName' from the TapplicationprojectKey using the HQL query.

Anyone know the way to work around this?

emmanuel · **Posted:** Mon Jul 25, 2005 2:22 am

DO NOT YELL on that forum, you won't get help this way.

dika151 · **Joined:** Thu Jul 21, 2005 10:25 pm **Posts:** 4

sorry.. i didn't know upper case means yelling.. didn't mean to yell.. just thought that if I use capitals then it'll get someone's attention faster than not.. well, i guess, it did anyway..

so.. do you have any idea?

ardal · **Posted:** Mon Jul 25, 2005 4:04 am

We are using composite keys, but we are querying using Criteria, not HQL, which works just fine.

http://www.hibernate.org/hib_docs/reference/en/html/querycriteria.html

Though, we are not using custom types to represent our composite keys, but the composite-key element in the hibernate maps.

dika151 · **Joined:** Thu Jul 21, 2005 10:25 pm **Posts:** 4

But, do you have a class named xxxxKey.java?

If you do have them, are you querying from that xxxxKey.java class or from xxxx.java (using criteria)?

ardal · **Posted:** Mon Jul 25, 2005 7:39 am

No, we are using the composite-id element in the maps:

Code:

<composite-id>
    <key-property name="ruleID" column="rule_id" type="java.lang.Integer">
         <meta attribute="use-in-equals">true</meta>
     </key-property>
     <key-property name="statatementID" column="statement_id" type="java.lang.Integer">
         <meta attribute="use-in-equals">true</meta>
       </key-property>
</composite-id>

So, I haven’t tried the using a custom key class (named xxxxKey.java). The map snipped form our statement.hbm.xml file and to get out the id’s from the composite keys using the criteria, we are using something like this code:

Code:

Criteria crit = sess.createCriteria(Statement.class);
List list = crit.list();

Statement myStatement = null; 
Iterator elements = list.iterator();
while(elements.hasNext()){
     myStatement = (Statement) elements.next();
     System.out.println("Id: " + myStatement.get StatementID());     
}

My best suggestion is for you to try to use this approach. Then your code would (maybe) look something like this:

Code:

Criteria crit = sess.createCriteria(Tapplicationproject.class);
List list = crit.list();

Tapplicationproject myObject = null; 
Iterator elements = list.iterator();
while(elements.hasNext()){
     myObject = (Tapplicationproject) elements.next();
     System.out.println("Id: " + myObject.getTapplicationprojectKey().getApplicationId())     
}