比如我們現在有一個Parent的實體,在Parent實體當中有一個children的Set由於這個children的資料並非非常重要,為了方便,我們在修改parent的時候,做法經常都是1,清空children全部刪了,再把新的children全部加進去。今天早上做這一方面工作的時候遇到一個問題,就是在更新parent的時候,報了一個Don't dereference a collection with cascade="all-delete-orphan"的異常,經常一半個小時的查資料和調試,
題目: A hard puzzleCrawling in process...Crawling failedTime Limit:1000MS Memory Limit:32768KB 64bit IO Format:%I64d & %I64uSubmitStatusPracticeHDU 1097Descriptionlcy gives a hard puzzle to feng5166,lwg,JGShining and Ignatius: gave a and
題目:ExponentiationTime Limit: 500MS Memory Limit: 10000KTotal Submissions: 100905 Accepted: 24250DescriptionProblems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the
題目地址:http://poj.org/problem?id=1007DNA SortingTime Limit: 1000MS Memory Limit: 10000KTotal Submissions: 63582 Accepted: 25103DescriptionOne measure of ``unsortedness'' in a sequence is the number of pairs of entries that are out of order with
題目連結:http://poj.org/problem?id=1927題目:Area in TriangleTime Limit: 1000MS Memory Limit: 30000KTotal Submissions: 1227 Accepted: 662DescriptionGiven a triangle field and a rope of a certain length (Figure-1), you are required to use the rope to
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).log4j:WARN Please initialize the log4j system properly.org.hibernate.MappingException: Unsupported cascade style: save_update at
就是最後的Apply security setting過不去提示:The security settings could not be applied to the database because the connection has failed with the following error.Error Nr. 1045Access denied for user 'root'@'localhost' (using password: YES)If a personal
資料來源配置時加上編碼轉換格式後出問題了:The reference to entity "characterEncoding" must end with the ';' delimiter這個錯誤就是 context.xml中設定資料來源連結URL的問題 <context-param> <param-name>url</param-name>
在使用spring交易管理時,程式報如下:org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only 程式的代碼為:serviceA.methiodA{ beforedone; methodB(); try{
題目: There's Treasure Everywhere!Crawling in process...Crawling failedTime Limit:1000MS Memory Limit:10000KB 64bit IO Format:%I64d & %I64uSubmitStatusDescriptionFinding buried treasures is simple: all you need is a map! The