Confuse with hibernate behaviour

fox_goblin · **Joined:** Thu Dec 07, 2006 4:30 pm **Posts:** 3

I made my DAOTest extends AbstractTransactionalDataSourceSpringContextTests. and try to persist 2 object with same unique key.

Quote:

<hibernate-mapping>
<class name="sample.domain.School" table="SCHOOL">
<id name="id" column="SCHOOL_ID" length="32">
<generator class="uuid"/>
</id>
<property name="name"/>
<property name="registerNumber" unique="true" not-null="true"/>
</class>
</hibernate-mapping>

However, the exception does not throw after I invoked the

Quote:

saveOrUpdate(school1)
saveOrUpdate(school2)

but if I flush the session or excute a query, the exception will be thrown out. Does it mean hibernate will not check the constraint when the instance is only saved to session, that job actually left to database?

fox_goblin · **Joined:** Thu Dec 07, 2006 4:30 pm **Posts:** 3

Following is my code.

I checked this page : Hibernate violate the unique key constraint, I flush the session before the second one commit, still got the problem.

Can anyone give me a hint about this?

http://www.hibernate.org/117.html#A8

Quote:

package sample;

import org.springframework.test.AbstractTransactionalDataSourceSpringContextTests;

import sample.dao.SchoolDAO;
import sample.domain.School;

public class SchoolDAOTest extends AbstractTransactionalDataSourceSpringContextTests {
private SchoolDAO schoolDAO;
private School school;
@Override
protected String[] getConfigLocations() {
return new String[]{"classpath*:context/*.xml"};
}

@Override
protected void onSetUpBeforeTransaction() throws Exception {
super.onSetUpBeforeTransaction();
schoolDAO = (SchoolDAO) this.applicationContext.getBean("schoolDAO");
school = new School();
school.setRegisterNumber("1");
}

public void testExceptionShouldBeThrownWhenUserTypeSameRegistrationKey() {
School school2 = new School();
schoolDAO.saveOrUpdate(school);
schoolDAO.getSessionFactory().getCurrentSession().flush();
school2.setRegisterNumber("1");
schoolDAO.saveOrUpdate(school2);
}
}

[url][/url]

lester · **Posted:** Fri Dec 08, 2006 4:54 am

Yes, this job (checking constraints) is left to database. Hibernate uses "write-behind" approch, that's why you recive an exception only after:
1. Query execution (Hibernate needs guarantee that objects, you've modified in session consistent with query results)
2. Commiting transaction
3. Explicit call Session.flush()

fox_goblin · **Joined:** Thu Dec 07, 2006 4:30 pm **Posts:** 3