Recommended practice for querying only some fields for objs.

adcworks · **Joined:** Fri Jun 18, 2004 10:17 am **Posts:** 140

I have a situation where I am loading a HTML page which lists many rows in a table. Each row represents an object called Schedule. I use Hibernate to manage persisting Schedule objects. Each Schedule has a Set collection and other String properties.

On my HTML table I only want to list 2 properties and the COUNT of the internal Set because it is taking quite a while for Hibernate to fully load all the Schedule objects which is what I have at the moment.

However, I do not know how to approach this problem because when I get to the JSP to render the HTML I want to iterate over a List to output the rows.

Do I have to create another object with only the 2 fields I want and an int for the count and then populate this using a specific HQL query? What is the general practice in this kind of situation?

Thanks!

anthony · **Posted:** Mon Jul 12, 2004 10:45 am

Code:

9.3.1. Scalar queries
Queries may specify a property of a class in the select clause. They may even call SQL aggregate functions. Properties or aggregates are considered "scalar" results. 

Iterator results = sess.iterate(
        "select cat.color, min(cat.birthdate), count(cat) from Cat cat " +
        "group by cat.color"
);
while ( results.hasNext() ) {
    Object[] row = results.next();
    Color type = (Color) row[0];
    Date oldest = (Date) row[1];
    Integer count = (Integer) row[2];
    .....
}
Iterator iter = sess.iterate(
    "select cat.type, cat.birthdate, cat.name from DomesticCat cat"
);
List list = sess.find(
    "select cat, cat.mate.name from DomesticCat cat"
);
[quote]

http://www.hibernate.org/hib_docs/reference/en/html/manipulatingdata.html#manipulatingdata-scalarqueries[/quote]

adcworks · **Joined:** Fri Jun 18, 2004 10:17 am **Posts:** 140

thanks. typo by the way .. should be...

Object[] row = (Object[]) results.next();