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)
