customer <- customer_address -> address and address type rel

[sonofseven]

hi there,

Imagine we have 4 tables
customer <- customer_address -> address & address_type
how would I go and implement this with EJB3? Is it possible?
I know that I can go one level down, but is it possible that I have just a class Customer that contains list of addresses of different type???

many thanks
rp

[ffray]

Sure you can. If your address types should be an entity it would
look like this:

package crm;

import javax.persistence.AccessType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;

@Entity (access=AccessType.FIELD)
public class AddressType {

 /**
 *
 */
 private static final long serialVersionUID = 3258135751752692024L;

 @Id(generate=GeneratorType.AUTO)
 private int id;

 @Column (length = 5)
 private String typeName;

 @Column (length = 50)
 private String description;
}

package crm;

import javax.persistence.AccessType;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;

@Entity(access = AccessType.FIELD)
public class Address implements Serializable {

 /**
 *
 */
 private static final long serialVersionUID = 3258135751752692023L;

 @Id(generate = GeneratorType.AUTO)
 private int id;

 @ManyToOne
 @JoinColumn(name = "addrType_id", referencedColumnName = "id")
 private AddressType addressType;

 private String street;

 private String zip;

 private String city;

 private String country;
}

package crm;

import java.util.Collection;

import javax.persistence.AccessType;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;

@Entity(access = AccessType.FIELD)
public class Customer implements Serializable {

 /**
 *
 */
 private static final long serialVersionUID = 3258135751752692025L;

 @Id(generate = GeneratorType.AUTO)
 private int id;

 private String name;

 @OneToMany(mappedBy = "customer_address")
 @JoinColumn(name = "cust_id", referencedColumnName = "id")
 private Collection<Address> addresses;

}

If you just flag the purpose of each address a customer has your code could look like the code shown above.
If you have real new types (means classes) of addresses you can inherit address like:

package crm;

import javax.persistence.AccessType;
import javax.persistence.Entity;

@Entity (access = AccessType.FIELD)
public class PrivateAddress extends Address {

 /**
 *
 */
 private static final long serialVersionUID = 3762257422173221171L;

 /* sth. useful here */
}

This code *SHOULD* work, just add usefule properties and the getters / setters.

Hope it helps

ff

[epbernard]

"ffray" wrote:
@OneToMany(mappedBy = "customer_address")
@JoinColumn(name = "cust_id", referencedColumnName = "id")
private Collection<Address> addresses;

}

This one is buggy, I think.
Either you have a customer_address *property* on the address side and @Joincolumn shouldn't be here
Or remove the mappedBy to make it the owner side.

Plus a @ManyToMany is probably more appropriate in your case.

[ffray]

Oh, my fault!
You're right! But i wouldn't like a @ManyToMany here since this would mean two distinct customers could share an address.
Well you could do that ... it depends on the usecase.
Looking for maximum redundant-free design m:n is correct but brings problems when one customer is moving (don't update the address!) and when entering new addresses (first search for identical address - 100% or unsharp? -, then use the existing one, otherwise insert the entered).
I don't know if this is what should be achieved. I think this should be a simple example.
So nevermind about the errors, it was a quickshot with a slight incorrect look at the @OneToMany Example at the spec.

Greetz

FF