java - Which solution has better performance when counting with hibernate -

i have 2 entities.one product , other productcategory.product productcategory relationship many one.i have method productcategories.i want add transient variable productcount productcategory shous how many products available each productcategory.i have 2 solutions these.both working fine.

solution 1

public list<productcategory> getproductcategorylist() {  list<productcategory> productcategorylist =             .getcurrentsession()             .createquery(                     "select pc productcategory pc")             .list();      (productcategory category : productcategorylist) {         string categoryid = category.getid().tostring();         category.setproductscount(getcurrentsession()                 .createquery(                         "select p product p  p.productcategory.id=:categoryid")                 .setparameter("categoryid", long.parselong(categoryid))                 .list().size());     } return productcategorylist; } 

solution 2

public list<productcategory> getproductcategorylist() {  list<productcategory> productcategorylist = new arraylist<productcategory>();     list<object[]> resultlist = this.getcurrentsession()             .createquery("from product p  right join  p.productcategory")             .list();      (object[] array : resultlist) {         product product = null;         productcategory productcategory = null;          if (array[1] != null) {             productcategory = (productcategory) array[1];         }         if (array[0] != null) {             product = (product) array[0];             productcategory.setproductscount(productcategory                     .getproductscount() == null ? 1 : productcategory                     .getproductscount() + 1);          }         if (productcategory != null                 && !productcategorylist.contains(productcategory)) {              productcategorylist.add(productcategory);          }      }      return productcategorylist; } 

what better solution these two? or other better solution ? don't have sound knowledge on comparison of performances in hibernate.

both of these solutions complex, , load products of categories database. if you're ready that, why don't make association bidirectional, , call category.getproducts().size() count?

if don't want that, should execute query categories, , execute single additional query product count database:

select category.id, count(product.id) product product inner join product.category category category.id in :categoryids group category.id 

this return list<object[]>, each object[] contains 1 of category ids, , associated count of products.