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a small question

 
leon ting
Greenhorn
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hi,what's a "dirty flag"? this name makes me uncomfortable.
and what's major difference between jdo and dao?which one is more useful?
 
Jeanne Boyarsky
author & internet detective
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Leon,
A dirty flag means that a data value has been changed in the object, but has not yet been written to the database.
 
Leandro Melo
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Data Access Object (dao) is a design pattern wich consists of a wrapper class the encapsulates all access (sql) to the database. Basically, you`d have something like

inside your session fa´┐Żade. Find more at http://java.sun.com/blueprints/corej2eepatterns/Patterns/DataAccessObject.html

Java Data Objects (jdo) is a standart. It`s used to implement your persistence model to the database, it provides its own api so you query, update, etc...
As Hibernate and other OR mappers, JDO is a techonology that might be taking entities bean`s place in a couple years.
http://java.sun.com/products/jdo/index.jsp
 
leon ting
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dear two upstairs:
your guide give me much.

with respect
 
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