storing key value pairs in hibernate | can we use map?

Question

I have a xml file and within which i have some key value pairs.I want to store them in form of key value pairs

<parent>
  <key1> value </1key>
  <key1> value </1key>
  <key1> value </1key>
  <key1> value </1key>
   ...
  <key1> value </1key>
</parent>

Now i dont know how many key value will be coming from xml in advance.How can i map it to hibernate object? i can stor it in table in

primaryKey parentId    key   value
   1          1         k1     val
   2          1         k2     val
   3          1         k3     val
   4          2         k1     val
   5          2         k2     val
   6          3         k3     val

How can i map it to hibernate object? I want following structure class Parent{ int parentId; String parent Name KeyValue keyval ; //How do i model it?

}

AM using netbeans IDE.

Answer 1

You may indeed use a map:

public class Parent {
    @Id
    private Integer id;

    @OneToMany(mappedBy = "parent")
    @MapKey(name = "key")
    private Map<String, KeyValuePair> keyValuePairs;
}

public class KeyValuePair {
    @Id
    private Integer id;

    @ManyToOne
    @JoinColumn(name = "parent_id")
    private Parent parent;

    @Column(name = "key")
    private String key;

    @Column(name = "value")
    private String value;
}

You should also have a unique constraint on [parent_id - key].