oracle 里的sequence号是什么，scn号是什么

答案:4 悬赏:40 手机版

解决时间 2021-01-11 23:55

提问者网友：心如荒岛囚我终老
2021-01-11 17:08

最佳答案

五星知识达人网友：执傲
2021-01-11 18:29

SCN：system change number
SCN是用于标示数据库变化的唯一标识号，其数值顺序递增。当执行事务时（DML语句、DDL语句），系统会为每个事务变化生成相应的SCN。当备份数据文件时，备份文件会记录备份点的SCN值，当恢复时，oracle会从备份点的SCN值开始恢复，一直到失败点的SCN值
sequence：日志序列号
日志序列号是重做日志的使用标识号，其数值也是顺序递增的。当进行日志切换时，日志序列号会自动增加1

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1楼网友：第四晚心情
2021-01-11 21:56

SELECt
time,
price,
SUM ( DECODE( TO_CHAr(time, 'MM') , '01', price, 0 ) ) AS m1,
SUM ( DECODE( TO_CHAr(time, 'MM') , '02', price, 0 ) ) AS m2,
SUM ( DECODE( TO_CHAr(time, 'MM') , '03', price, 0 ) ) AS m3,
SUM ( DECODE( TO_CHAr(time, 'MM') , '04', price, 0 ) ) AS m4,
SUM ( DECODE( TO_CHAr(time, 'MM') , '05', price, 0 ) ) AS m5,
SUM ( DECODE( TO_CHAr(time, 'MM') , '06', price, 0 ) ) AS m6,
SUM ( DECODE( TO_CHAr(time, 'MM') , '07', price, 0 ) ) AS m7,
SUM ( DECODE( TO_CHAr(time, 'MM') , '08', price, 0 ) ) AS m8,
SUM ( DECODE( TO_CHAr(time, 'MM') , '09', price, 0 ) ) AS m9,
SUM ( DECODE( TO_CHAr(time, 'MM') , '10', price, 0 ) ) AS m10,
SUM ( DECODE( TO_CHAr(time, 'MM') , '11', price, 0 ) ) AS m11,
SUM ( DECODE( TO_CHAr(time, 'MM') , '12', price, 0 ) ) AS m12
FROM
timeprice
GROUP BY
time,
price
如果对您有帮助，请记得采纳为满意答案，谢谢！祝您生活愉快！
vaela

2楼网友：煞尾
2021-01-11 19:23

sequence = 序列
scn = SYSTEM CHANGE NUMBER

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