Mapping primary key and foreign key

reisito · **Joined:** Tue May 17, 2005 6:23 am **Posts:** 5

Hi All
I am very new to hibernate and little confused about primary key and foreignkey in .hbm.xml file.
Lets say I have a table called , User which has following fields
ID (Primary key)
User name
Password

I have another table called User_Details
User_Details
ID (PK+Foreign key to user table)
First Name
Last Name
Address
City
Country

Now I want to creater .hbm.xml files for both the tables how do I do that?
I dont have any tool which will generate these files automatically, so I have to really do it by myself.

Please advise how do I achieve this?

borak · **Posted:** Tue May 24, 2005 8:54 am

reisito wrote:

Hi All
I am very new to hibernate and little confused about primary key and foreignkey in .hbm.xml file.
Lets say I have a table called , User which has following fields
ID (Primary key)
User name
Password

I have another table called User_Details
User_Details
ID (PK+Foreign key to user table)
First Name
Last Name
Address
City
Country

Now I want to creater .hbm.xml files for both the tables how do I do that?
I dont have any tool which will generate these files automatically, so I have to really do it by myself.

Please advise how do I achieve this?

First of your association logic is completely wrong, here this is a "one-to-one" association, If it is not a neccesity, do not use 2 tables for 1 object. This means extra join queries.

reisito · **Joined:** Tue May 17, 2005 6:23 am **Posts:** 5

Thanks for your reply,
But honestly if I want to create one-to-one relationship ex: Relationship between a book and sales, a book must have one sales record and a sales record is associated with one specific book in this case how do we achieve above stated goal?

pksiv · **Posted:** Tue May 24, 2005 9:45 am

reisito wrote:

Hi All
I am very new to hibernate and little confused about primary key and foreignkey in .hbm.xml file.
Lets say I have a table called , User which has following fields
ID (Primary key)
User name
Password

I have another table called User_Details
User_Details
ID (PK+Foreign key to user table)
First Name
Last Name
Address
City
Country

Now I want to creater .hbm.xml files for both the tables how do I do that?
I dont have any tool which will generate these files automatically, so I have to really do it by myself.

Please advise how do I achieve this?

With your original example above, you might want to look at the example at http://www.hibernate.org/41.html which talks about using a lightweight class.

However with the Book/Sales example, you can specify something like this:

Code:

<hibernate-mapping">
  <class name="Book" table="BOOK">
    <id column="ID" name="id" type="java.lang.Long">
       <generator class="native"/>
    </id>
    <property column="TITLE"  name="bookTitle" type="java.lang.Long"/>
     .... additional properties....
    <one-to-one name="sale" class="Sale" cascade="...."/>        
  </class>
    
  <class name="Sale" table="SALE">
     <id column="ID" name="id" type="java.lang.Long">
        <generator class="foreign">
           <param name="property">book</param>
        </generator>
     </id>
     <one-to-one name="book" class="Book" constrained="true"/>
     <property column="SALE_DATE"  name="saleDate" type="java.util.Date"/>
     .... additional properties....
  </class>  
</hibernate-mapping>

The foriegn ID generator will save the ID of the Sale using the generated ID provided by the book.

borak · **Posted:** Tue May 24, 2005 9:46 am

Read part 5.1.11 one-to-one mapping, it does what exactly you want

pksiv · **Posted:** Tue May 24, 2005 9:50 am

borak wrote:

Read part 5.1.11 one-to-one mapping, it does what exactly you want

Section 6.1.11 in version 3.0.3 and greater