How do we count rows using older versions of Hibernate 2009

Question

For example  if we have a table Books  how would we count total number of book records with hibernate

User · Answer

You could try count      Integer count    Integer  session createQuery  select count    from Books   uniqueResult      Where Books is the name off the class - not the table in the database

User · Answer

It s very easy  just run the following JPQL query   int count      Number      entityManager      createQuery           select count b               from Book b        getSingleResult     intValue      The reason we are casting to Number is that some databases will return Long while others will return BigInteger  so for portability sake you are better off casting to a Number and getting an int or a long  depending on how many rows you are expecting to be counted

User · Answer

For older versions of Hibernate   lt 5 2    Assuming the class name is Book   return  Number  session createCriteria  Book                      setProjection Projections rowCount                       uniqueResult      It is at least a Number  most likely a Long

User · Answer

Long count    Long  session createQuery  select count    from  Book   uniqueResult

User · Answer

This works in Hibernate 4 Tested    String hql  select count    from  Book   Query query  getCurrentSession   createQuery hql   Long count  Long  query uniqueResult    return count    Where getCurrentSession   is    Autowired private SessionFactory sessionFactory    private Session getCurrentSession    return sessionFactory getCurrentSession

User · Answer

Here is what official hibernate docs tell us about this   You can count the number of query results without returning them      Integer  session createQuery  select count    from        iterate   next     intValue     However  it doesn t always return Integer instance  so it is better to use java lang Number for safety

User · Answer

In Java i usually need to return int and use this form   int count     Long getSession   createQuery  select count    from Book   uniqueResult    intValue

User · Answer

If you are using Hibernate 5   then query will be modified as  Long count   session createQuery  select count 1  from  Book                        getSingleResult      Or if you Need TypedQuery   Long count   session createQuery  select count 1  from  Book  Long class                           getSingleResult

[java] How do we count rows using older versions of Hibernate (~2009)?

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