JPA/Hibernate with Dynamic Object Model

Question

I have a table with the number of column is variable (depend of customer), so I looking for a way to mapping this table with a java object using JPA/Hibernate or other

I can not use POJO because it's limited to a stable table so I'd like to use java object like this

class MyObject {
int id;
Map<String, Object> fields = new  Map<String, Object>();

public void setId(int id) { 
    this.id = id; 
}

public void setField(String key, Object value) { 
    fields.put(key, value);
}

}

The table for storing MyObject :

TABLE MYTABLE (
ID INTEGER,
FIELD1 VARCHAR, 
FIELD2 DATE, 
FIELD3 INTEGER
)


MyObject myObject = new MyObject();
myObject.setId(id);
myObject.setField("FIELD1" , "hello world");
myObject.setField("FIELD2" , new Date());
myObject.setField("FIELD3" , 21)

Action to save myObject in db;

And of course the possibility to query

If you are not aware of your schema. You should go for Nosql. Eg. Mongo — cody123
– cody123, Commented Sep 29, 2016 at 11:36
Thank you for your answer, but I am constraint to use relationale database (sqlserver for now) — OliDem
– OliDem, Commented Sep 29, 2016 at 12:03
See dynamic models docs.jboss.org/hibernate/core/3.3/reference/en/html/… — Alan Hay
– Alan Hay, Commented Sep 29, 2016 at 12:12
Thanks Alan, it's looks interesting. In your link v(3.3) it said : The following features are currently considered experimental and may change in the near future. In v5 no this notice, I hope hibernate will keep and maintains this fonctionality. Unfortunatly the documentation is pretty lite. But in the idea, this is match with my goal — OliDem
– OliDem, Commented Sep 29, 2016 at 13:58

Alan Hay · Accepted Answer · 2016-09-29 15:05:07Z

4

Hibernate supports what they refer to as Dynamic Models. See further the following link which notes:

Persistent entities do not necessarily have to be represented as POJO/JavaBean classes. Hibernate also supports dynamic models (using Maps of Maps at runtime). With this approach, you do not write persistent classes, only mapping files.

http://docs.jboss.org/hibernate/orm/5.1/userguide/html_single/Hibernate_User_Guide.html#dynamic-model

Previous versions of the Hibernate docs give some more detail. See:

http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html_single/#persistent-classes-dynamicmodels

There's an example here that seems (from a quick skim) to allow for combining normal POJO with dynamic fields.

https://www.infoq.com/articles/hibernate-custom-fields

edited Sep 29, 2016 at 15:05

answered Sep 29, 2016 at 14:57

Alan Hay

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1 Comment

OliDem Over a year ago

thanks again Alan, I have found this link also : what-when-how.com/hibernate/…

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