-Describe differences between Hibernate and JPA 

   JPA is a standard (JEE)
   Hibernate is a JPA provider ***
   Hibernate provides additional features beyond the JPA standard
   Hibernate is a third-party framework
   We typically configure JPA with annotations, Hibernate with XML

- What are the names for common Hibernate XML configuration files? 

   hibernate.cfg.xml (if JPA persistence.xml)
   <classname>.hbm.xml

- Hibernate programs can be portable across databases. 
  What features of Hibernate contribute to that?

   HQL is portable
   Hibernate lets us specify a database "dialect" (like JDBC "adapter")
 
- Hibernate programs can create queries and manage object 
   state transitions like transient -> persistent. 
   What Hibernate type lets us do that?

    Event e = new Event();   -- transient
    session.save(e);         -- makes e "managed"
 
- List at least three techniques that Hibernate provides 
    so apps can issue queries. What are the advantages of each?

   HQL
   native SQL
   Criteria
   Query By Example
   Filter (controls the generated SQL adding additional predicate(s))

- Hibernate supports mapping inheritance hierarchies 
   to the database. What are the strategies and their pros and cons? 

   Single Table
          - Good: No joins needed - fast
          - Bad: have to NULLABLE columns, not normalized, discriminator
   Joined (table per class)
          - Good: Normalization, no discriminator 
   Table per Concrete Class
          - Rarely used

- Discuss the Hibernate entity lifecycle and its states.

   transient - not managed (new object)
   persistent - in the persistence context
   detached - not in PC; close session, evict(), clear()
   removed - marked for deletion
 
- Hibernate entities must have a primary key. 
  What are the options for keys that Hibernate supports?

   identity
   sequence
   assigned
   increment 
   
    composite keys 

- Hibernate entities can have relationships. 
   How do we implement such relationships in the database?

    unidirectional, bidirectional
    single value, multivalued

    foreign keys
    join table    
 
- Discuss syntax differences between Hibernate Query 
   Language (HQL) and standard SQL. 

   from Event  (HQL) entity NAME!

   select * from events