Introduction to JDO

WalkingWithJava

this introduction beses on kodo tutorial,see more information on it if necessary

chapter1: (p11)
what´s jdo?
what´s persistent data?
what´s transparent persistence?

chapter3: some common conceptions about jdo (p14)
1>JDOHelper:
2>PersistenceManager
3>PersistenceCapable
4>Transaction
5>Extent
6>Query

chapter4 PersistentCapable
1>what´s JDO Enhancer  p16
2>Restrictions on Persistent Classes   p17
    1.if u define a constructor ,provide a public no-arg constructor also.
    2.see reference which type can be supported p18
    3.remember the restriction on operating Array p19
3>InstanceCallbacks
not a common use .it might be used when the persisten object has some fields cannot persistent directly     by Jdo,see reference here if necessary p20

4>Jdo Identity :tests whether two persistent objects represent the same state in the data store
refereces about datastore identity and application identity .app id is more common

chapter5 Metadata
1>Metadata has three primary purposes:to identify persistence-capable classes.to override default JDO       behavior.
2>how to use Metadata.see example
3>placement:if define a class Magazine in package org/mag/.the jdo should:
    1.org/mag/Magazine.jdo
    2.org/mag/package.jdo
    3.org/package.jdo
    4.package.jdo
4>the JDO Metadata can be named as class-name.jdo or package.jdo

chapter6 JDOHelper
1>main usage:get persistenceManagerFactory.see the samples on p35

chapter7 PersistenceManagerFactory
1>we specify properties on a file.but if u want to specify it at runtime,see samples on P36
2>references:Properties and Supported Options p40

chapter8 PersistenceManager.
some operations about data bese p44
1>makePersistent:like insert data into DB
2>deletePersistent:delete
3>samples about operations above: p46-p47
the PersistenceManager is the factory about Extent and Query also

chapter9 Transaction
see samples on p49-51

chapter10 Extent
remember close Extent when operation finished p52

chapter11 Query samples on p55-p57
1>basic query: p55
2>ordering result: p55
3>use filter
4>methods like "in " in jdbc
5>query using map of parameters.(like preparedStatement in jdbc)