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什么时候使用嵌入式对象数据库
When to use an Embedded ODBMS
http://www.theserverside.com/tt/articles/article.tss?l=EmbeddedODBMS
所谓嵌入对象数据库,因为关系数据库和对象如同水和火不可融合,一山不容二虎,因此,一个系统要么以关系数据库为核心(对象为辅助),要么以对象为核心(数据库为辅助),很显然在使用一个OO语言体系下,无疑数据库必须是对象的辅助,这就是Embedded ODBMS ,就是在Java/.NET的应用中运行数据库,将数据库作为程序的一个附属持久特性。
If an O/R mapping tool is being used, then a new mapping section will have to be added to the mapping file. And, in both cases, a new database table (possibly more than one) will have to be created. In short, adding a new persistent class goes beyond simply adding the class; an entourage of additional infrastructure must be assembled.
In a true ODBMS, none of the above work is necessary. For example, using the open-source object database, db4o, the programmer simply begins storing the new objects, and the database is automatically adjusted to accept them. The db4o engine invisibly discovers the new class structure (via reflection) and performs all the behind-the-scenes tasks to store the new object type. There is no administrative work, no new tables need to be added, and no mapping entries must be written.
db4o与Hibernate区别就是无需写mapping配置文件。