package com.lyq.dao;

import java.util.List;

import com.lyq.persistence.Category;
import com.lyq.util.HibernateFilter;
/**
 * ҩƷ�����ݿ������
 * @author Li Yong Qiang
 */
public class CategoryDao extends SupperDao {
	
	/**
	 * ���id��ѯ���
	 * @param id 
	 * @return Category
	 */
	public Category loadCategory(int id){
		Category c = null;
		try{
			session = HibernateFilter.getSession();		//��ȡSession����
			session.beginTransaction();					//��������
			//���������Ϣ
			c = (Category)session.load(Category.class, new Integer(id));
			session.getTransaction().commit();			//�ύ����
		}catch(Exception e){
			e.printStackTrace();						//��ӡ�쳣��Ϣ
			session.getTransaction().rollback();		//�ع�����
		}
		return c;
	}
	/**
	 * ��ѯ�������
	 * @return List
	 */
	public List findAllCategory(){
		List list = null;
		try{
			session = HibernateFilter.getSession();		//��ȡSession����
			session.beginTransaction();					//��������
			list = session.createQuery("from Category c")//����Query����
						  .list();						//��ȡ���
			session.getTransaction().commit();			//�ύ����
		}catch(Exception e){
			e.printStackTrace();						//��ӡ�쳣��Ϣ
			session.getTransaction().rollback();		//�ع�����
		}
		return list;
	}
	/**
	 * ͳ��ҩƷ�������
	 * @return
	 */
	public List findCategoryAndCount(){
		List list = null;
		try{
			session = HibernateFilter.getSession();		//��ȡSession����
			session.beginTransaction();					//��������
			// �����Ӳ�ѯ���
			String hql = "select c.name,count(*) from Medicine m join m.category c group by c";
			list = session.createQuery(hql)//����Query����
						  .list();						//��ȡ���
			session.getTransaction().commit();			//�ύ����
		}catch(Exception e){
			e.printStackTrace();						//��ӡ�쳣��Ϣ
			session.getTransaction().rollback();		//�ع�����
		}
		return list;
	}
}