ConstraintViolationException problem at db insert

shekinskiy · **Joined:** Wed Dec 14, 2005 11:36 am **Posts:** 3

hi,

i wanna insert an object (Car in example) whose foreign key object (Company in example) may not exist. But i don't know how i should design mapping document. In other words Company may not exists, but i want to save cars into db.

Hibernate version: 3.1

Mapping documents:

Code:

Company.hbm
...
<bag name="carList" cascade="none" inverse="false" lazy="true">
            <key column="`nCompanyId`"/>
            <one-to-many class="Car"/>
</bag>
...
Car.hbm
...
<many-to-one name="company" column="`nCompanyId`"/>
...

Code between sessionFactory.openSession() and session.close():

Code:

t = session.beginTransaction();
session.save(car);
t.commit();

Full stack trace of any exception that occurs:
org.hibernate.exception.ConstraintViolationException: could not insert: [object.Car]
....
Caused by: java.sql.SQLException: Cannot insert the value NULL into column 'nCompanyId', table 'mydb.dbo.Car'; column does not allow nulls. INSERT fails.
.....
Name and version of the database you are using: MS SQL Server 2000 SP4

The generated SQL (show_sql=true):

Code:

insert into Car ( [nCompanyId], [dAmount], [sDetail] ) values (?, ?, ?)
// values are (0, 0.0, 'anything') respectively

jlawmi · **Joined:** Mon Nov 24, 2003 6:36 pm **Posts:** 105

If Company is a "lookup" type of table, then I think the mapping is incorrect.

Do you have a separate mapping for Car, or does it only exist w/ in the context of a company?

Try making Car its own entity, and using many:1 to company- the lookup.

James

shekinskiy · **Joined:** Wed Dec 14, 2005 11:36 am **Posts:** 3

If Company is a "lookup" type of table, then I think the mapping is incorrect.
i can't understand meaning of "lookup". i also think the mapping is incorrect, but i dont know how i can correct.

Do you have a separate mapping for Car, or does it only exist w/ in the context of a company?
i have seperate mapping file (hbm) for both: Company and Car. In previous mail i have sent relationship between these tables. i need this realtionship becouse i get list of "car left outer join car.company".

Try making Car its own entity, and using many:1 to company- the lookup.
explain with example please

abg1979 · **Joined:** Fri Sep 09, 2005 11:35 am **Posts:** 101

how did you create the database schema. i think hibernate is doing the right thing by trying to insert null for company column. Is this column nullable in the database.

Also you can try using

Car.hbm
...
<many-to-one name="company" column="`nCompanyId`" not-null="false"/>

shekinskiy · **Joined:** Wed Dec 14, 2005 11:36 am **Posts:** 3

i don't use any tool to create my schemas.

company table:

Code:

nCompanyId          sName         ....
1                           Alfa             ....
2                           Beta            ....

car table

Code:

nCarId      nCompanyId      dAmount      ....
1              1                       0.0              ....
2              1                       0.0              ....
3              2                       0.0              ....

i can insert all rows above using my schema and hibernate, but i cant insert row bellow, because company whose nCompanyId is '0' does not exist. And i want to insert row bellow but how?

Code:

[b]car table[/b]
nCarId      nCompanyId      dAmount      ....
4              0                       0.0              ....

OK, i have added not-null param and altered table respective column null allowed

New Error Message

Code:

org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before
 flushing: object.Company
.......

LaLiLuna · **Posted:** Wed Jan 18, 2006 1:07 pm

when car cannot exist without your company than must save your company first.
comp = new Comp();
car = new Car();
car.setComp(comp);
session.save(company);
// ad you defined cascade="none" you must also save car explicitly.
session.save(car);

...
if comp exist do
comp = (Comp) session.get(Comp.class, id);
car.setComp(comp);
session.save(car);

Regards Sebastian