My problem is simple:
A user has an address, address is composed of city, state and country.
So for that I have this structure:
public class User {
..
//bi-directional many-to-one association to UserAddress
#ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
#JoinColumn(name="id_user_address")
private UserAddress userAddress;
..
}
Note that CascadeType does not have CascadeType.ALL because if the user is deleted it won't affect the cities, states and countries created.
public class UserAddress {
..
//bi-directional many-to-one association to AddressCity
#ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.})
#JoinColumn(name="id_city")
private AddressCity addressCity;
//bi-directional many-to-one association to AddressCountry
#ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
#JoinColumn(name="id_country")
private AddressCountry addressCountry;
//bi-directional many-to-one association to AddressState
#ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
#JoinColumn(name="id_state")
private AddressState addressState;
..
}
My problem is if I try to register a user that has the same city for example it gives me an exception:
SEVERE: Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'Campinas' for key 'city_UNIQUE'
How can I avoid this kind of constraint, keeping the CASCADE?
And anyone know how to show the queries made by JPA in my JSF project?
The CascadeType.PERSIST annotation for User.userAddress causes userAddress to be persisted for each User persisted and CascadeType.PERSIST annotation for UserAddress.addressCity causes addressCity to be persisted for each UserAddress persisted. Thus when you persist a user with same city, new city is tried to be persisted with the same key which causes constraint violation. So remove the cascades for those ManyToOne annotated relationships.
You have to check on saving User whether userAddress already exists and check on saving UserAddress whether the relationships inside it already exist and take required action.
Related
I have a scenario where I have the user table and the address table. The address table is a value objects in domain driven design in my understanding. How do I store value objects in mysql database? this sounds a bit confusing but I couldn't understand this idea value objects are immutable but how to store them?
Below are classes of my two entity
user.java
#Getter #Setter #NoArgsConstructor
#Entity // This tells Hibernate to make a table out of this class
#Table(name="user")
public class User {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#JsonProperty("userid")
#Column(name="userid")
private Long user_id;
#JsonProperty("user_nome")
private String nome;
#JsonProperty("user_email")
#Column(unique = true, nullable = false)
private String email;
#JsonProperty("user_cpf")
private String cpf;
#JsonProperty("user_telefone")
private String telefone;
#JsonProperty("user_celular")
private String celular;
#JsonProperty("user_senha")
private String senha;
#Column(name="createdAt", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP")
#Temporal(TemporalType.TIMESTAMP)
#JsonProperty("user_createdAt")
private Date createdAt;
#Column(name="updateAt", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP")
#Temporal(TemporalType.TIMESTAMP)
#JsonProperty("user_updateAt")
private Date updateAt;
/*Person p1 = new Person("Tom", "Smith");
p1.setId(1L);
p1.setStartDate(new Date(System.currentTimeMillis())); */
}
class Address:
#Getter #Setter #NoArgsConstructor
#Entity // This tells Hibernate to make a table out of this class
#Table(name="address")
public class Address {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#JsonProperty("address_id")
private Long address_id;
#JsonProperty("address_endereco")
private String endereco;
#JsonProperty("address_bairro")
private String bairro;
#JsonProperty("address_numero")
private String numero;
#JsonProperty("address_complemento")
private String complemento;
#JsonProperty("address_cidade")
private String cidade;
#OneToOne(fetch=FetchType.LAZY)
#JoinColumn(name = "userid")
private User userid;
}
Basically however you want: you could enforce immutability in the database, but you don't have to. Immutability can be enforced in the database by creating an unique constraint on a combination of values of an address, zipcode + house number for example.
As a database administrator I personally don't like developers enforcing immutability in the database because I see implementing/enforcing business logic in the database as a category error. What is an immutable value within the domain, to me is just data that needs to be consistently stored. Database rules are meant to ensure data consistency and the added complexity of implementing immutability in the database can interfere with that. Lets do a thought experiment:
You ensure that an address value is unique in the database with a constraint that covers all properties and store your data. Some time later a customer places an order that happens to have the same address, but he lives on the North Pole. The order is saved but the address isn't because my server throws an error because the address violates the constraint because it already exsists in the US, but that's not saved/part of the constraint. Now I have a problem because that orphaned order violates the data model, you complain to me because my server threw an error and now it's up to me to figure out what's wrong with your design decision to apply the abstract concept of immutability outside your domain, and have to update the data definition in a production environment in order to fix it.
So I think it's best you acknowledge that by storing data it leaves your domain and that is a risk your design should take into account. What I'd advice (or silently implement haha) would be the addition of an ID within the table and a record versions of the same 'immutable value' for tracability, consistency and agility to react to unforseen circumstances. Just like with user and transaction entities ;)
I am working with EclipseLink and JPA 2.0.
Those are my 2 entities:
Feeder entity:
#Entity
#Table(name = "t_feeder")
public class Feeder implements Serializable {
private static final long serialVersionUID = 1L;
//Staff
#OneToMany(cascade = CascadeType.ALL, mappedBy = "idAttachedFeederFk")
private Collection<Port> portCollection;
//staff
}
Port entity:
#Entity
#Table(name = "t_port")
public class Port implements Serializable {
//staff
#JoinColumn(name = "id_attached_feeder_fk", referencedColumnName = "id")
#ManyToOne
private Feeder idAttachedFeederFk;
//staff
}
And this is my code:
Feeder f = new Feeder();
//staff
Port p = new Port();
p.setFeeder(f);
save(feeder); //This is the function that calls finally persist.
The probleme is that, only feeder is persisted and not the port. Am I missing something? And specially, in which side should I mention the cascading exactly. Given that in my database, the port table is referencing the feeder one with a foreign key.
EDIT
This simple piece of code worked fine with me:
public static void main(String[] args) {
Address a1 = new Address();
a1.setAddress("madinah 0");
Employee e1 = new Employee();
e1.setName("houssem 0");
e1.setAddressFk(a1);
saveEmplyee(e1);
}
I am not sure why you would expect it to work: you are attempting to save a new instance of Feeder which has no connection whatsoever to the newly created Port.
By adding the Cascade to the #OneToMany and calling save(feeder) Eclipse link would if there were an association:
Insert the record for the Feeder.
Iterate the Port collection and insert the relevant records.
As I have noted however, this new Feeder instance has no Ports associated with it.
With regard to your simple example I assume when you say it works that both the new Address and Employee have been written to the database. This is expected because you have told the Employee about the Address (e1.setAddressFk(a1);) and saved the Employee. Given the presence of the relevant Cascade option then both entities should be written to the database as expected.
Given this it should then be obvious that calling save(port) would work if the necessary cascade option was added to the #ManyToOne side of the relationship.
However if you want to call save(feeder) then you need to fix the data model. Essentially you should always ensure that any in-memory data model is correct at any given point in time, viz. if the first condition below is true then it follows that the second condition must be true.
Port p = new Port();
Feeder feeder = new Feeder();
p.setFeeder(f();
if(p.getFeeder().equals(f){
//true
}
if(f.isAssociatedWithPort(p)){
//bad --> returns false
}
This is obviously best practice anyway but ensuring the correctnes of your in-memory model should mean you do not experience the type of issue you are seeing in a JPA environment.
To ensure the correctness of the in-memory data model you should encapsulate the set/add operations.
I was very impress with my project, but suddenly I notice that I am doing something very wrong, 'cause, every create, merge, delete I was doing manually, but I should let the JPA take care of that for me right ?
What I do, is create the database then create the entities from it. So here is my database so you guys can understand my concept issue.
In a simple way:
An user has an address, only one address. This address is composed by city, state and country. I want to be able to create, update the user address by cascade.
I think my mapping, generated by JPA is wrong (or my understaing is wrong), let me show it:
public class User {
..
//bi-directional many-to-one association to UserAddress
#ManyToOne(cascade = CascadeType.ALL) // should be one to one ?
#JoinColumn(name="id_user_address")
private UserAddress userAddress;
..
}
public class UserAddress {
..
//bi-directional many-to-one association to User
#OneToMany(mappedBy="userAddress", fetch=FetchType.EAGER)
private List<User> users;
//bi-directional many-to-one association to AddressCity
#ManyToOne
#JoinColumn(name="id_city")
private AddressCity addressCity;
//bi-directional many-to-one association to AddressState
#ManyToOne
#JoinColumn(name="id_state")
private AddressState addressState;
//bi-directional many-to-one association to AddressCountry
#ManyToOne
#JoinColumn(name="id_country")
private AddressCountry addressCountry;
..
}
What I think is that the user has one adress only, so it should be OneToOne mapping ?
And the same goes for UserAdress about country, state and city.
If you want to allow multiple users on the same address #ManyToOne is what you want. If you use #OneToOne you can have only one user per address.
I have 2 tables with #ManyToMany relation field. In hibernate cfg i have
<property name="hbm2ddl.auto">update</property>
Table which is created during application startup has UNIQUE key set on PartId column, which is
#JoinColumn(name="PartId")}
in #ManyToMany relation. I didn't set anywhere that this column should have unique key. Is this the default auto creation behaviour?
The DB is MySQL 5.5
Thanks.
UPD:
Full field desc is:
#ManyToMany
#JoinTable(name="Part_Dev",
joinColumns={#JoinColumn(name="PartId")},
inverseJoinColumns= {#JoinColumn(name="DevCode")})
public List<Dom> getDom() { return dom; }
UPD 2
sorry, I see I didn't mention it. Unique key in Parts table,
#Entity #Table(name="Parts")
public class Parts implements Serializable{
#ManyToMany
#JoinTable(name="Part_Dev",
joinColumns={#JoinColumn(name="PartId")},
inverseJoinColumns= {#JoinColumn(name="DevCode")})
public List<Dom> getDom() {
return dom; }
#Column(name="PartId")
public Integer getPartId() {
return partId; }
you need to specify #JoinTable to make it happen. For instance, if you have two entities : Employee and Project in a many-to-many relationship. You need to have #JoinTable on one side.
#Entity
public class Employee {
#Id private int id;
private String name;
#ManyToMany
#JoinTable(name="EMP_PROJ",
joinColumns=#JoinColumn(name="EMP_ID"),
inverseJoinColumns=#JoinColumn(name="PROJ_ID"))
private Collection<Project> projects;
So, as Chris told, that was the way to identify each part.
I am getting a list of entities and attempting to add more values to it and have them persist to the data base... I am running into some issues doing this... Here is what I have so far...
Provider prov = emf.find(Provider.class, new Long(ID));
This entity has a many to many relationship that I am trying to add to
List<Organization> orgList = new ArrayList<Organization>();
...
orgList = prov.getOrganizationList();
So I now have the list of entities associated with that entity.
I search for some entities to add and I place them in the orgList...
List<Organization> updatedListofOrgss = emf.createNamedQuery("getOrganizationByOrganizationIds").setParameter("organizationIds", AddThese).getResultList();
List<Organization> deleteListOfOrgs = emf.createNamedQuery("getOrganizationByOrganizationIds").setParameter("organizationIds", DeleteThese).getResultList();
orgList.addAll(updatedListofOrgss);
orgList.removeAll(deleteListOfOrgs);
As you can see I also have a list of delete nodes to remove.
I heard somewhere that you don't need to call persist on such an opperation and that JPA will persist automatically. Well, it doesn't seem to work that way. Can you persist this way, or will I have to go throught the link table entity, and add these values that way?
public class Provider implements Serializable {
#Id
#Column(name="RESOURCE_ID")
private long resourceId;
...
#ManyToMany(fetch=FetchType.EAGER)
#JoinTable(name="DIST_LIST_PERMISSION",
joinColumns=#JoinColumn(name="RESOURCE_ID"),
inverseJoinColumns=#JoinColumn(name="ORGANIZATION_ID"))
private List<Organization> organizationList;
...//getters and setters.
}
The link table that links together organizations and providers...
public class DistListPermission implements Serializable {
#Id
#Column(name="DIST_LIST_PERMISSION_ID")
private long distListPermissionId;
#Column(name="ORGANIZATION_ID")
private BigDecimal organizationId;
#Column(name="RESOURCE_ID")
private Long resourceId;
}
The problem is that you are missing a cascade specification on your #ManyToMany annotation. The default cascade type for #ManyToMany is no cascade types, so any changes to the collection are not persisted. You will also need to add an #ElementDependent annotation to ensure that any objects removed from the collection will be deleted from the database. So, you can change your Provider implementation as follows:
#ManyToMany(fetch=FetchType.EAGER, cascade=CascadeType.ALL)
#ElementDependent
#JoinTable(name="DIST_LIST_PERMISSION",
joinColumns=#JoinColumn(name="RESOURCE_ID"),
inverseJoinColumns=#JoinColumn(name="ORGANIZATION_ID"))
private List<Organization> organizationList;
Since your Provider class is managed, you should not need to merge the entity; the changes should take effect automatically when the transaction is committed.