Mapping and relations in database ....

Question

Hello Friends,
I'm a bit new to Toplink so i need your help. I am working with snort Rules.
I have 5 tables in my datbase. one table is the parent table. Rules. The other tables are child tables. Addresses, Ports, Flags and values.
I have a GUI interface from where i can inser a new Rule in the table - I have the primary key created by a sequence in each table. A rule contains everything .. i mean IP addresses, Ports, different Flag Values and some other variable values. Now i want to create relations between the tables.
The rules table has one to many relationship with address address, ports and values table. And address table has many to one relationship with rules. Can anybody help me how can i create relationship between tables.
I have written some code by but i am getting errors. The code is as follows.
In rules table i have written this code.
public class Rules implements Serializable {               
@OneToMany
     (mappedBy="rules", targetEntity= Address.class, fetch=FetchType.EAGER )
     private Address address;
Address table has a colum with SID as foreign key.
public class Address implements Serializable {
@ManyToOne(optional=false)
@JoinColumn(name="SID",referencedColumnName="SID")
private Rules rules;
Kindly help me and let me know what is tha problem with this code.
Many thanks in advance.

Answer 1

If one Address can be in more than one Rule, then you do not have a OneToMany relationship, you have a ManyToMany relationship. So make both relationships a Collection and use the @ManyToMany annotation. You will also need to have a JoinTable for the relationship on the database, use a mappedBy on one side of the relationship.
See,
http://en.wikibooks.org/wiki/Java_Persistence/ManyToMany
James : http://www.eclipselink.org