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Hibernate Criteria API - update many rows with one database query

I'm fetching from database bunch of persons like this:
public List<Object[]> getLimitedBunchOfPersons(Integer limit) {
Criteria criteria = getSession().createCriteria(Person.class, "person")
.setProjection(
Projections.projectionList()
.add(Projections.property("person.personId"), "personId")
)
.createAlias("person.status","status")
.add(Restrictions.eq("status.statusId", 1L))
.addOrder(Order.asc("person.createdOn"));
return criteria.setMaxResults(limit).list();
}
As I needed to speed things up, I only fetched ID's of my entity. Important thing to note is that I'm manipulating with large number of rows and for one query had to use maxResults limitation.
Now my problem is, how to easily update with Hibernate Criteria API in one database query all fetched rows from previously mentioned query?
Plain SQL query would go something like this:
UPDATE PERSON
SET STATUS = 2, CREATED_ON = CURRENT_TIMESTAMP
WHERE STATUS = 1;
It's important to note that update method have to use same order and limit as getLimitedBunchOfPersons() method.

For Single Object it will work as follows after your code
Person per= (Person) criteria.uniqueResult();
per.setCreatedOn("crtBy");
currentSession.merge(per);
Now if comes in list you can iterate list by passing mentioned code in your List iteration

How can I correctly implement an Hibernate SQL query starting from an SQL query that count the number of rows?

I am absolutly new in Hibernate and I have the following problem.
I have this standard SQL query:
SELECT count(*)
FROM TID003_ANAGEDIFICIO anagraficaEdificio
INNER JOIN TID002_CANDIDATURA candidatura
ON (candidatura.PRG_PAR = anagraficaEdificio.PRG_PAR AND candidatura.PRG_CAN = anagraficaEdificio.PRG_CAN)
INNER JOIN TID001_ANAGPARTECIPA anagPartecipa ON(anagPartecipa.PRG_PAR = candidatura.PRG_PAR)
INNER JOIN anagrafiche.TPG1029_PROVNUOIST provNuovIst ON (provNuovIst.COD_PRV_NIS = anagPartecipa.COD_PRV_NIS)
WHERE anagraficaEdificio.FLG_GRA = 1 AND provNuovIst.COD_REG = "SI";
This works fine and return an integer number.
The important thing to know is that in this query the only
parameter that can change (inserted by the user in the frontend of a webappplication) is the last one (this one: provNuovIst.COD_REG = "SI").
So, the application on which I am working use Hibernate and the requirement say that I have to implement this query using Hibernate Native SQL, I have found this tutorial:
http://www.tutorialspoint.com/hibernate/hibernate_native_sql.htm
that show this example:
String sql = "SELECT * FROM EMPLOYEE WHERE id = :employee_id";
SQLQuery query = session.createSQLQuery(sql);
query.addEntity(Employee.class);
query.setParameter("employee_id", 10);
List results = query.list();
that, from what I have understand (correct me if I am doing wrong assertion), involves the use of an Employee model class. So th prvious query first define the query (using the :param_name syntax for the parameter), then create an SQLQuery Hibernate object, add the class used for the result, set the previous parameter neam and finally obtain a List (that I think Hibernate create as something like an ArrayList) with the retrieved object.
My problem is that I simply I have to obtain an integer value (because I have a SELECT count(*), so I will obtain an integer value and not a set of rows).
So how can I correctly use the Hibernate Native SQL to implement my SQL query into my Hibernate repository class?

Use SQLQuery.uniqueResult to retrieve a single value from the query:
String sql = "SELECT count(*) ...";
SQLQuery query = session.createSQLQuery(sql);
// set parameters...
int count = ((Number)query.uniqueResult()).intValue();

H2 database default value of TIMESTAMP column

I am writing integration tests with H2 database.
My database (generated) initialization include this script (because generated join table does not have this column):
ALTER TABLE INT_USR ADD IU_INSDTTM TIMESTAMP DEFAULT NOW();
This is how I create records:
Integration integrationOne = createIntegration(firstId, "FIRST");
Integration integrationTwo = createIntegration(secondId, "SECOND");
flushAndClear();
userService.logRecentIntegration(integrationOne.getId(), user.getId());
flushAndClear();
userService.logRecentIntegration(integrationTwo.getId(), user.getId()); //1
The method logRecentIntegrations(.., ..) just calls the DAO and the dao does this:
Query query = entityManager.createNativeQuery(
"INSERT INTO INT_USR (USR_ID, INT_ID) VALUES (?, ?)");
query.setParameter(1, userId)
.setParameter(2, integrationId);
query.executeUpdate();
Later in my test:
Query query = entityManager.createNativeQuery(
"SELECT * FROM INT_USR ORDER BY IU_INSDTTM");
List resultList = query.getResultList();
When I debug this test in resultList there are two records (correct) but they have same timestamp. Even when I inserted a breakpoint on line marked //1 and waited a while - so the time gap between inserts would be significant. (Thread.sleep - same result)
I tried to modify the SQL script to
ALTER TABLE INT_USR ADD IU_INSDTTM TIMESTAMP DEFAULT CURRENT_TIMESTAMP;
But with same result. Why both results have same timestamp?

As documented, the function CURRENT_TIMESTAMP always returns the same value within a transaction. This behavior matches other databases, for example PostgreSQL.

You may add the following annotation to your test to disable transactions.
#Transaction(propagation = Propagation.NEVER)
Note: That annotation comes from Spring and there may be something else for the environment that you are running within.

Note that if you're generating hibernate pojo's you can also use CreationTimestamp. I just tried it and it seemed to work!
#CreationTimestamp
protected LocalDateTime createdDate;

How to use update hibernate query using setMaxResults?

I hope it is the appropriate section, I have a problem with this code
Transaction transaction = session.beginTransaction();
Query query = session.createQuery("update database set floop= :ctrl1" +" where ctrl= :ctrl2 ").setMaxResults(2);
query.setMaxResults(2);
query.setParameter("ctrl1",3);
query.setParameter("ctrl2", 5);
I ask through setMaxResults(2) to do the update only on the first two and he makes the update of all records as I do what is wrong?? thanks for any help
I thought to use session.createSQLQuery, but I do not know how to do.

This answer is posting delay but it can be helpful for others user who is looking update number of rows in DB with limit using HQL
Unfortunatly setMaxResults() do not work update and delete hibernate
query. It works only select criteria.
As per HQL there is no specific solution is available and you want to update rows with number of limit then follow below steps
Write a HQL to select all rows with condition or range with
setMaxResults. It will return you a List object with limit.
Then update the specific property (Property you want to update) and
store Objects of these rows again by session.update() method.
I'm assuming tablename with map Database class and there are two variable ctrl and floop with getter and setter(as per your question)
List<Database> list = new ArrayList<>();
Transaction transaction = session.beginTransaction();
//Fetching record with limit 2 using setMaxResults()
int setlimit = 2;
String hql_query = "from Database where ctrl = :ctrl2";
Query select_query = session.createQuery(hql_query).setMaxResults(setlimit);
select_query.setParameter("ctrl2", 5);
list = select_query.list();
//iterating list and setting new value to particuler column or property
int result;
if (list != null) {
for (Database element : list) {
element.setFloop(ctrl1);
//Here is updating data in database
session.update(element);
}
result = list.size();
} else {
result = 0;
}
System.out.println("Rows affected: " + result);
transaction.commit();

setMaxResults limits the number of results which are returned by the query, not the number of affected rows.
When you only want to update a limited set of rows, you should specify these rows within the where condition. Setting a hard limit on the number of updated rows wouldn't make much sense, because there would be no way to tell which rows would be updated.

query.setMaxResults(2); will be used for selection queries and will be ignored for insertion/updation. If you use it for selection queries, then you will get 2 records in result.

setMaxResults only applies to select. For your problem I would perform a select query and then use the query.setMaxResults(2), this will return a list of max 2 elements. Then loop the list returned and use session.update for the one or two elements returned.

I can see a number of perfectly valid use-cases where you want to update only a limited number of rows and as other have already answered, the Hibernate Query cannot deal with this so you need to resort to native SQL.
You don't specify in the question which type of database you are using so this answer will only apply to MySql:
Transaction transaction = session.beginTransaction();
Query query = session.createSQLQuery("UPDATE database SET floop= :ctrl1 WHERE ctrl= :ctrl2 LIMIT :max");
query.setParameter("ctrl1",3);
query.setParameter("ctrl2", 5);
query.setParameter("max", 2);
Please note that the sql query above needs to use the native table and column names and not the ones in your ORM model.

Hibernate update not working

I am new with hibernate and I was trying to update a mapped object with the following code, but it does not update
factory = config.buildSessionFactory();
session = factory.getCurrentSession();
Transaction t = session.beginTransaction();
String hql = "UPDATE "+tableName+" SET "+columnName+" = '"+columnValue+"' WHERE id ="+id+";";
Query query=session.createSQLQuery(hql);
t.commit();
Am I missing something? It do not crash nor update the record.
NOTE: I am using Hibernate3 and Mysql

You're missing query.executeUpdate();
Also, if you're updating a mapped object I would recommend you to make the changes to the java object, and let Hibernate do the update for you. Or at least use a hql query, not a native one.
Make sure that your persistence.xml file has show_sql set to true and watch the log to see if the update is executed.
<property name="hibernate.show_sql" value="true"/>

You need to use query.executeUpdate() to run the query.
Also it is suggested that you use parameters instead of inline arguments. For eg. if the columnName = O'Reilly then the whole query will go wrong.
Also if it is a mapped object you can use HQL rather than SQL query
Instead you can use this
//entity is your hibernate entity obj
String hql = "UPDATE " + entity.getClass().getName + " as entity SET entity." + fieldName + "= :columnValue WHERE entity = :entity";
Query query=session.createQuery(hql).setParameter("columnValue", columnValue).setParameter("entity", entity);
query.executeUpdate();
Notice that you don't need to use single quotes. setParameter handles it.