Hibernate and keyvalue pair implementation

Question

I would like to create a few classes which are in essense wrapper of a map of key value pair. What is the best appoarch to retrieve or store these classes into a database using hiberate? What are the right hibernate annotations to get the job done?

On the database, I would expect this formation of data

class1, field1, value1
class2, field2, value2
class1, field2, somevalue1
...

On the java side, I may have

@Table("some_db_table")
class KeyValuePairs {

  private HashMap<String, String> map;
...
}

class Class1 extends KeyValuePairs {
  private Stirng id = "class1";
...
}

class Class2 extends KeyValuePairs {
  private Stirng id = "class2";
...
}

Answer 1

I guess you have a ready-made implementation here http://www.java2s.com/Code/Java/Hibernate/HibernateCollectionMappingMap.htm

Check if this is helpful (You can create your subclasses just the way you mentioned)? That generates two tables which is a good practice since you want to keep your primary key that is not being used for business logic. IF you dont want it then you can always tweak it.