truth be told , consistent is very easy to understand. it means oracle should protect data is consistent.
so how to do so ? SCN is the best way to protect when oracle fetch data ,but you know, when you fetch data,there are a lot of user is changing data. so when transcation is start. then record the scn.
if block scn> recored scn, than means this data can't use. because it's changed.
原帖由 tom_fans 于 2010-8-27 15:01 发表
truth be told , consistent is very easy to understand. it means oracle should protect data is consistent.
so how to do so ? SCN is the best way to protect when oracle fetch data ,but you know, when you fetch data,there are a lot of user is changing data. so when transcation is start. then record the scn.
if block scn> recored scn, than means this data can't use. because it's changed.
顶
原帖由 tom_fans 于 2010-8-27 15:01 发表
truth be told , consistent is very easy to understand. it means oracle should protect data is consistent.
so how to do so ? SCN is the best way to protect when oracle fetch data ,but you know, when you fetch data,there are a lot of user is changing data. so when transcation is start. then record the scn.
if block scn> recored scn, than means this data can't use. because it's changed.
恩,我也是这么理解的!