SELECT location_id, city FROM locations l WHERE NOT EXISTS (SELECT location_id FROM departments WHERE location_id l.location_id); 请问各位谁能给我讲讲应该如何理解这个not exists吗，如果是exists ...

olsnode 命令 具体都可以-help查看 [root@dmk01 bin]# ./olsnodes -help Usage: olsnodes [-n] [-p] [-i] [ | -l] [-g] [-v] where -n print node number with the node name ...

看书说一个事务内的sql语句要么全部执行成功，要么全部不成功，大家看看下面怎么回事，希望帮助解答 create table a (id number); insert into a values(1); insert into a values(2); insert into a values(b); com ...

我对柱状图理解不够深刻，希望大师们指点

相老师您好： 最近一个项目：Goldengate同步完后，用veridata校验，数据不一致，但在源和目标端查询数据是一致的。 根据goldengate日志，对于无主键的表在目标端同步的时候，是不会把blob字段作为唯一性的 ...

数据库版本 是RAC SQL> select * from v$version ; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - ...

Required competencies and technical skills: 1. Comprehensive understanding of Oracle database concepts and hands-on experience as a DBA (5+ years industry experience on very large Oracle database per ...

刚刚创建好的数据库 SQL> startup ORACLE 例程已经启动。 Total System Global Area 2137886720 bytes Fixed Size 2177456 bytes Variable Size 1241515600 bytes Database Buffers ...