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Hibernate乐观锁之Timestamp注意点

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Jun 07, 2016 pm 04:49 PM

lt;timestamp name=updDate column=UPD_DATEgt;lt;/timestampgt; 这个必须跟在id定义之后这使用AP服务器的时间，而不是

这个必须跟在id定义之后

这使用AP服务器的时间，而不是DB服务器的时间，来更新数据库。

即更新数据库时使用的是new Date()，，而不是sysdate。

如果要使用DB服务器时间来更新DB，必须加上source="db"

此时，hibernate会先从数据库中取出当前时间（select sysdate from dual），然后再用该时间进行更新。

并不是严格意义上的用sysdate更新数据库（update table1 set upd_date=sysdate ……）。

如果更新结果中没有毫秒信息，请检查Dialect，应使用org.hibernate.dialect.Oracle10gDialect。（Oracle9及其后续版本应该都支持毫秒）

不要使用org.hibernate.dialect.OracleDialect，该类已经被Deprecated。

使用org.hibernate.dialect.Oracle10gDialect之后，取DB时间的SQL会变为 select systimestamp from dual。

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