Hibernate executes SQL to obtain generic objects

 

See the following SQL query example:

Private void test ()

{

// Obtain the hibernate Session Object

Session session = hibernateutil. currentsession ();

// Start the transaction

Transaction Tx = session. begintransaction ();

// Write SQL statements

String sqlstring = "select {S. *} from student s where S. name like 'marjun '";

// Create a sqlquery object using an SQL statement

List L = session. createsqlquery (sqlstring)

// Associate the queried records with specific entities

. Addentity ("S", student. Class)

// Return all Record Sets

. List ();

// Traverse the result set

Iterator it = L. iterator ();

While (it. hasnext ())

{

// Because the query result is associated with the student class, the returned student set

Student s = (student) it. Next ();

Set enrolments = S. getenrolments ();

Iterator iter = enrolments. iterator ();

While (ITER. hasnext ())

{

Enrolment E = (enrolment) ITER. Next ();

System. Out. println (E. getcourse (). getname ());

}

}

// Submit the transaction

TX. Commit ();

// Close the session

Hibernateutil. closesession ();

}

The preceding example shows how to associate a query record with an object. In fact, SQL queries also support converting query results into scalar values. You can use the addscalar method to convert them into scalar values, for example:

Double max = (double) Session. createsqlquery ("select max (Cat. weight) as maxweight from cats cat ")

. Addscalar ("maxweight", hibernate. Double );

. Uniqueresult ();