Question

I am trying to use subquery function in my Hibernate query, but I’am an idiot 🙂 Structure of my DB tables is:

CREATE TABLE standard (
  id VARCHAR(12) NOT NULL ,
  title VARCHAR(99) NOT NULL ,
  description VARCHAR(999) NOT NULL ,
  revision VARCHAR(99) NOT NULL ,
  annotation TEXT NULL ,
  PRIMARY KEY (id) );

CREATE TABLE article (
  id VARCHAR(12) NOT NULL ,
  type INT(2) NOT NULL ,
  classTitle VARCHAR(99) NULL ,
  classDescription VARCHAR(999) NULL ,
  standard_id VARCHAR(12) NULL ,
  pubdate DATETIME NOT NULL ,
  title VARCHAR(99) NULL ,
  thumbnail TEXT NULL ,
  text TEXT NULL ,  
  PRIMARY KEY (id) );

What I’m going to do is to get standard, which contains articles with specified type. My thought was that I filter articles by its type, then group them by its standardId and then get standards through its ids.

Something like this 🙂

DetachedCriteria subquery = DetachedCriteria.forClass(Article.class)
                             .add(Restrictions.eq("type", Constants.ARTICLE_TYPE_INTERPRETATION))
                              .setProjection(Projections.groupProperty("standardId"));

List<Standard> stds = (List<Standard>) session.createCriteria(Standard.class)
            .add(Restrictions.idEq(Subqueries.exists(subquery))).list();

But this query gives me all of the standards in database despite the fact, that subquery returns only standard that I want. I know where the problem is : I can’t write the Restriction that will filter standard by its ids returned by subqery.

Can someone give me a hint how to do it ?

Many thanks !

Ondrej

EDIT:
Thanks to @Rahul Agrawal

List<Standard> stds = (List<Standard>) session.createCriteria(Standard.class)
            .add(Subqueries.propertyIn("id", subquery)).list();

Answer 1

Add an IN condition.
To add a “where field in subquery”, two separate criteria are required. One for the main (root) entity, and the other to retrieve the values for the IN list.
The following retrives the orders for which it has an order item which the product has a stock level of ZERO. The result transformer is used to only retrieve one row per entity, instead of having multiple rows as a result of the join on a one-to-many relationship.
?

DetachedCriteria ids = DetachedCriteria.forClass(ProductStock.class, "stock");
ids.add(Restrictions.eq("stock.stockLevel", 0));
ids.setProjection(Property.forName("productId"));

DetachedCriteria criteria = DetachedCriteria.forClass(Order.class, "order");
criteria.createAlias("order.orderItems", "items", CriteriaSpecification.LEFT_JOIN);
criteria.add(Subqueries.propertyIn("items.productId", ids));
criteria.setResultTransformer(Criteria.ROOT_ENTITY);

For more details refer : http://devgrok.blogspot.in/2008/11/hibernates-criteria-api.html