Question

I have table with following table schema :

I have created a method that returns the list of value on query execution.

    protected List findAllWithGroupClause(Class clazz) {

    List objects = null;
    try {
        startOperation();
        String SQL_QUERY = "SELECT COUNT(serviceName) AS RunningInstances ,serviceName,SUM(numberofthread) as workerThread "
                + "FROM servicemanagerdetails WHERE servicemanagerstatus=:status GROUP BY serviceName";
        Query query = session.createQuery(SQL_QUERY);
        query.setString("status", "Running");
        objects = query.list();
        tx.commit();
    } catch (HibernateException e) {
        handleException(e);
    } finally {
        HibernateFactory.close(session);
    }
    return objects;
}

and for that declared ServiceManagerDetails.hbm.xml file:

  <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class name="com.arosys.hibernatedatamanager.ServiceManagerDetails" table="servicemanagerdetails">
    <id column="servicedetailsid" name="servicedetailsID" type="integer">
      <generator class="increment"/>
    </id>
    <property column="serviceID" name="servicemanagerID" type="string"/>
    <property column="servicemode" name="servicemode" type="string"/>
    <property column="servicetype" name="servicetype" type="string"/>
    <property column="servicemanagerstatus" name="servicemanagerstatus" type="string"/>
    <property column="controlqueue" name="controlQueue" type="string"/>
    <property column="controlexchange" name="contolExchange" type="string"/>
    <property column="controlroutingkey" name="controlRoutingkey" type="string"/>
  </class>
</hibernate-mapping>

i have created column alias for that it is necessary to write setter and getter method as well as define mapping?please explain how can retrieve value from list.

Thanks

Answer 1

You have a select statement for selecting aggregate functions COUNT, SUM etc. In this case the hibernate Query.list() returns a list of arrays of objects.

If you want to get the SUM of the fourth row, you do

Object obj4[] = objects.get(3);
long sum4 = ((Number)obj4[2]).longValue();

and for the serviceName of the third row you do

Object obj3[] = objects.get(2);
String name2 = (String)obj4[2];

(both examples for explaining; your code will look more variable).

You do not need to write getters and setters, you even can’t do that. You can’t use the column aliases outside the select string.