I m 使用谷歌和JDO。 在不必首先冲淡数据储存内容的情况下,如何更新JDO类定义?
我不敢肯定这一点是否具体针对关于公认会计原则的JDO,但我注意到,当我简单地将我的一个持久性领域的名称从<代码>svotes改为votes
时,就出现了一个例外(java.lang.NoSuch FieldError: svotes
)。
我预计,一旦我的现场走到现场,我可能会想对我的初专干事类别定义作一些改动,例如增加一个领域或一个东西。 关于如何更新数据定义而不必冲淡数据库的任何建议?
I m 使用谷歌和JDO。 在不必首先冲淡数据储存内容的情况下,如何更新JDO类定义?
我不敢肯定这一点是否具体针对关于公认会计原则的JDO,但我注意到,当我简单地将我的一个持久性领域的名称从<代码>svotes改为votes
时,就出现了一个例外(java.lang.NoSuch FieldError: svotes
)。
我预计,一旦我的现场走到现场,我可能会想对我的初专干事类别定义作一些改动,例如增加一个领域或一个东西。 关于如何更新数据定义而不必冲淡数据库的任何建议?
http://code.google.com 准则也可适用于 j。
http://code.google.com/appengine/docs/java/datashop/creating Recanddeletingdata.html”rel=“nofollow noreferer”>here?
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