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 Post subject: Oracle's ROWID as PK
PostPosted: Thu Apr 14, 2005 4:36 pm 
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Joined: Thu Apr 14, 2005 4:10 pm
Posts: 1
I am using Hibernate 3 and Oracle 9.

I am working with legacy tables that cannot be changed. Many of these tables do not have a primary key. I tried working with a composite-id of all of the columns in the table, but ran into problems with duplicate rows and null values. Finally, I came up with the solution of using ROWID as a primary key. Everything was working smoothly.

I was using this code to generate all Classification objects with the given serial number. No problems.

Code:
Criteria criteria = session.createCriteria(Classification.class);
criteria.add(Expression.eq("serialNo", serialNo));   
list = criteria.list();


Then, it came time to optimize. I read somewhere that HQL queries in the mapping could increase performance due to caching. I tried this out on one of my classes that does not use ROWID and it did increase the speed. So, I changed the above code to

Code:
Query query = session.getNamedQuery("Classification.getBySerialNo");
query.setLong("serialNo", serialNo);
list = query.list();


to go with the HQL in Classification.hbm.xml

Code:
<hibernate-mapping

   <class name="Classification" table="XML_AP_CLASSIFICATION" mutable="false">
   <cache usage="read-only"/>   
   <id column="ROWID" name="id">
      <generator class="native"/>
   </id>
      
   <property column="SERIAL_NO" name="serialNo" type="long"/>
   <property column="INTERNATIONAL_CODE_TOTAL_NO" name="internationalCodeTotalNo" type="string"/>
   <property column="US_CODE_TOTAL_NO" name="usCodeTotalNo" type="string"/>
   <property column="INTERNATIONAL_CODE" name="internationalCode" type="string"/>
   <property column="US_CODE" name="usCode" type="string"/>
   <property column="STATUS_DATE" name="statusDate" type="com.nameprotect.tm.hibernate.us.dao.util.StringDateType"/>
   <property column="FIRST_USE_ANYWHERE_DATE" name="firstUseAnywhereDate" type="com.nameprotect.tm.hibernate.us.dao.util.StringDateType"/>
   <property column="FIRST_USE_IN_COMMERCE_DATE" name="firstUseInCommerceDate" type="com.nameprotect.tm.hibernate.us.dao.util.StringDateType"/>
   <property column="PRIMARY_CODE" name="primaryCode" type="string"/>

   <property column="STATUS_CODE" name="statusCode" type="com.nameprotect.tm.hibernate.us.dao.code.ClassStatusCode$UserType" />

   </class>

   <query name="Classification.getBySerialNo"><![CDATA[
      from Classification where serialNo = :serialNo
   ]]></query>

</hibernate-mapping>


This caused problems with the ROWID. With the Criteria way, hibernate was generating this SQL:

select this_.ROWID as ROWID0_, this_.SERIAL_NO as SERIAL2_6_0_, ....

but with the HQL way, it is generating this SQL:

select classifica0_.ROWID as ROWID, classifica0_.SERIAL_NO as SERIAL2_4_, ....

This causes a problem because ROWID is special for Oracle and cannot be used as the alias. I have narrowed the problem down to org.hibernate.mapping.Column.getAlias().

Does anyone have any suggestions or workarounds?


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 Post subject:
PostPosted: Fri Apr 15, 2005 1:47 am 
Hibernate Team
Hibernate Team

Joined: Tue Aug 26, 2003 6:10 am
Posts: 8615
Location: Neuchatel, Switzerland (Danish)
put a *small* runnable example together and post it in the jira.

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