Hi,

We need to migrate our persistence layer code written in pure jdbc call to Hibernate.
We are facing below mentioned issues in migrating the same.

1) For Insert ,update ,delete operation ,since our object model and DB Model are in sync we are able to sucessfully port the code to HQL.

2) For select and select List operation ,the object model and database model are completely out of sync and therefore implemention while converting it to HQL we faced below mentioned issues.

2.1) Since the Object and tables are unrelated we were not able to implement joins(Outer Joins)

Theerfore with reference to above mentioned issues what will be the best possible alternatives.

Regards
Rajeev

Do you meant: for insert ,update ,delete operation you are able to sucessfully port the code to Hibernate.
Or do you really explicitly call HQL (Hiberante-Query-Language) queries in order to realize inserts, updates and delete operations ?
(Latter would be a very unusual approach to use Hibernate).

Hi,

yes we are sucessfully able to port insert update and delete queries.
but we are not able to port select statement due to the problem mentioned
above.

Regards
Rajeev Kumar Pandey

Hi,

apparently you did not understand what I intended to ask.
Do you use session.save(newobject) or entityManager.persist(newobject) in order to do new inserts,
or do you something like session.createQuery("....").executeUpdate() ?

Hi,

I am using session.save(Object obj) and session.update(Object obj) for my insert and update opertaion.

Regards
Rajeev

OK, that's good.

What do you mean indeed with


Do you have no relations (fields which acts as foreign keys) between your tables?
What is 'the Object' ?

Hi,

For select and selectList operation we are using right outer join query specific to oracle and our table do not have any association based on foreign keys.

From Object i mean my domain Model.

we are fetching the data from multiple table using oracle sql query and using a seperate pojo to populate the fecthed results.

Regards
Rajeev

So on what are your associations based, if not on foreign keys ?
Can you show some concrete example?

By the way,
in Hibernate you can also use session.createSQLQuery(String sql) which accepts queries in SQL-syntax,
so there you could place the join-queries you usually used with plain jdbc.

Hi,

As mentioned earlier there is no association between the tables and we are fetching the data using
theta style joins.

To your suggestion regarding using createSQLQuery(String sql) the sql will be oracle specific and we will not be able to achieve the complete db independence.

Some one susggest that converting all our oracle specific sql statement to ANSI sql which is supported by multiple DB's.
Please suggest.

Regards
Rajeev

Can you show some example of concrete theta style joins?
Usually joins are made over foreign keys, so I wondering what you are joining.
(For me a foreign key must not mandatory have a constraint defined on it.
As soon a field refers to a primary key of another table, it is a foreign key logically seen).