hi

I have Person and Address classes. There is a unidirectional relationship between these two. When my program starts i get all the persons from the database (also all the addresses that have a relation with some person) but some other time i need all the addersses, so i check all the addresses form database.

since i get them in different sessions

person1.getAddress() == address1

returns false. but i want them to be equal.

Is secondary cache can solve this problem?
If not is there any way of handling this situation?
What is the harm of not closing a session?

Check out this link on the Hibernate wiki: http://www.hibernate.org/109.html

Also look at the reference manual.

Implement equals() correctly and use

if (person.getAddress().equals(address)){
}

i know this,
but what i want is there must be only one copy of the address class in the memory. i mean what i want is object identity.
is there any way of doing it by hibernate, if not i will do it manual.

also i have another question.

cfg.configure("hibernate.cfg.xml");
SchemaExport su = new SchemaExport(cfg);
su.setOutputFile("schema.txt");
su.create(true,true);
sf = cfg.buildSessionFactory();

when i say su.create it drops all the tables. what i want is if the tables doesnot exist than create, if they do exist then do nothing.
and last one question can we create database by hibernate?

[quote="e120281"]when i say su.create it drops all the tables. what i want is if the tables doesnot exist than create, if they do exist then do nothing. [quote]
How far does this get you?

thanks dennis.

again the same question --> what i want is there must be only one copy of the address class in the memory. i mean what i want is object identity.
is there any way of doing it by hibernate, if not i will do it manual.

You will need to do following:

1. Implement correct equals method in Address.java. This equals() method needs to do deep comparison i.e. it needs to check all the properties of Address object while determining if given 2 objects are same.

2. person.getAddress().equals(addressObj)

Ron
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