而且这个人一旦断开,能够及时通知服务器
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写一个触发器，设置标志位！
至于“而且这个人一旦断开,能够及时通知服务器“
需要客户端的控制！
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ALTER PROFILE p1 LIMIT SESSIONS_PER_USER 1;
assign p1 to that user: ALTER USER scott
PROFILE p1
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ALTER PROFILE p1 LIMIT SESSIONS_PER_USER 1;
assign p1 to that user: ALTER USER scott
PROFILE p1
this is the only way: ofcourse 一次只能一个用户使用.
the second user can not get connected .
oracle has a session concept , the session is kept openning between client and server .