Hibernate Notes

• API
  Core Interfaces
  • Session
  • SessionFactory
  • Configuration
  • Transaction
  • Query and Criteria
  Callback Interfaces
  • Lifecycle
  • Validatable
  • Interceptor
• Configuration: XML and annotations
• Configuration: Managed vs. Unmanaged
• Object identity: identity vs. equality, primary keys (natural and surrogate keys)
• Object model
  Entity vs. value types
  • entity has its own database identity (primary key value)
  • value type has no database identity; is embedded in row of owning entity (except collections)
  
  Components of classes
  • allows separate class to be value object - lifecycle dependent on owning class
  • Can be bidirectional (using "parent" element, but usually unidirectional
  
  Mapping of inheritance
  • Table per concrete class
  • Table per class hierarchy
  • Table per subclass
  
  Associations
  • Unidirection <many-to-one> : simplest, reference foreign key in owned class definition
  • Bidirectional <many-to-one>,<one-to-many> : use <set> with child <one-to-many> and child <key> into owned class (also needs "inverse" attribute on <set> element)