JPA Multiple Embedded fields with prefix?

Question

With JPA annoations, I want to reuse same embedded object like this :

@Entity
public class User {
    @Embedded
    public Address homeAddress;

    @Embedded
    public Address workAddress;
}

@Embeddable
public class Address {
    public String code;
    public String city;
    ...
} 

I can specify SQL column names with @AttributeOverrides, @AttributeOverride and @Column, but it's verbos. Is it possible to specify just a prefix to add to each column for homeAddress and workAddress ?

Thanks,

Xavier

Answer 1

If you would like to use multiple same Embedded class. You have to do @AttributeOverrides for all columns. Try as below;

Reference JPA AttributeOverrides

@Embeddable
public class Address {
    private String state;
    @Column(name = "zip_code")
    private String zip;
}

@Entity(name = "Employee")
public class Employee implements Serializable {
    @Embedded
    @AttributeOverrides({
        @AttributeOverride(name = "state", column = @Column(name = "province_1")),                       
        @AttributeOverride(name = "zip", column = @Column(name = "postal_code_2"))
    })
    private Address address_1;  

    @Embedded
    @AttributeOverrides({
        @AttributeOverride(name = "state", column = @Column(name = "province_2")),                       
        @AttributeOverride(name = "zip", column = @Column(name = "postal_code_2"))
    })
    private Address address_2;  

}   

My suggestion, if there are one or more Embedded value in your Entity. Try to use @CollectionTable.

@CollectionTable(name = "EMPLOYEE_ADDRESS", joinColumns = @JoinColumn(name = "ADDRESS_ID"))
private List<Address> addressList;

Reference JPA CollectionTable

Answer 2

adding this works for me (i'm using hibernate as JPA provider though)

<property name="hibernate.implicit_naming_strategy" value="org.hibernate.boot.model.naming.ImplicitNamingStrategyComponentPathImpl" />

Answer 3

In 2022 (after 9 Years) @zaw-than-oo -s answer is still valid :-( .

This "Duplicate" answer is for reference if sombody wants to improve jpa-embedded.

Here is a working crossplatform example based on @zaw-than-oo -s answer with verbose java-jpa and easy to use android-room

@androidx.room.Entity
@javax.persistence.Entity
@javax.persistence.Inheritance(strategy = javax.persistence.InheritanceType.SINGLE_TABLE)
public class AppHardware {
    @javax.persistence.Id
    @javax.persistence.GeneratedValue(strategy = javax.persistence.GenerationType.AUTO)
    @androidx.room.PrimaryKey(autoGenerate = true)
    private int id;

    // max is embedded without column renaming
    @androidx.room.Embedded
    @javax.persistence.Embedded
    private ProfileCommon max;

    // min is embedded with column renaming
    @androidx.room.Embedded(prefix = "min")
    @javax.persistence.Embedded
    @javax.persistence.AttributeOverrides({
        // Verbose: every persisted property in ProfileCommon needs an entry
        // see https://stackoverflow.com/questions/12912063/jpa-multiple-embedded-fields-with-prefix
        @AttributeOverride(name = "added", column = @Column(name = "minadded")),
        @AttributeOverride(name = "apkName", column = @Column(name = "minapkName")),
        @AttributeOverride(name = "versionCode", column = @Column(name = "minversionCode")),
        @AttributeOverride(name = "versionName", column = @Column(name = "minversionName")),
        @AttributeOverride(name = "size", column = @Column(name = "minsize"))
        
    })
    private ProfileCommon min;

    // getter and setter onmitted
}

@javax.persistence.MappedSuperclass
public class ProfileCommon  {
    private long added; // date
    private String apkName;
    private long versionCode;
    private String versionName;
    private long size;

// getter and setter onmitted
}