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目前顯示的是 十二月, 2013的文章

Google Application Engine開發筆記

GAE (1.7.4):取得上傳日期String applicationVersion =SystemProperty.applicationVersion.get();Date uploadDate =newDate(Long.parseLong(applicationVersion.substring(applicationVersion.lastIndexOf(‌​".")+1))/(2<<27)*1000); Ref: SystemProperty
JPA 2 限制:
Simple JoinEntity Group Transaction
An entity’s parent, parent’s parent, and so on recursively, are its ancestors; its children, children’s children, and so on, are its descendants. An entity and its descendants are said to belong to the same **entity group**_._
一般我們常常在一個transaction內大量修改同一類型物件,例如修改多個User的資料,這就算 Cross Group Transaction操作,最多不能超過5個entity group。 參考資料:
Google App Engine JPA test casesimple join works on unowned one-to-many relationship.limitation: Problem with query : Joins can only be sorted by the join column in ascending order (in this case
‘attendeeList’)開發GAE會遇到的問題 Maven 若使用JPA,datanucleus plugin 的設定官方文件未提及,不方便,很容易跟project 依賴的版本不合。我參考
http://www.loop81.com/2013/02/gae-google-app-engine-jpa2-maven-and.html
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