Pessimistic concurrency is not a scalable option when users are interacting with data and causing records to be locked for relatively large periods of time 如果用户与数据进行交互，会使记录锁定相对长的时间，保守式并发并不是可伸缩的选项。
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Is there a mechanism to maintain data record locking in the backend database when the end - user is working on the data accessed through a jsf sdo service data objects based web client 在最终用户通过基于jsf / sdo （服务数据对象）的web客户机进行数据访问时，在后端数据库中有没有维护数据/记录锁定的机制？
