Oracle 视图 USER_JOINGROUPS 官方解释,作用,如何使用详细说明
本站中文解释
Oracle视图USER_JOINGROUPS是非常有用的,它用于显示指定用户是哪些组的成员。Oracle视图USER_JOINGROUPS拥有以下三个字段:
USER_NAME:用户名字;
GROUP_NAME:组名称;
IS_MEMBER:用户是否是指定组的成员(Y/N)。
使用视图USER_JOINGROUPS后,可以判断指定用户是否是某组成员:
SELECT * FROM USER_JOINGROUPS WHERE USER_NAME=’张三’ AND GROUP_NAME=’testGroup’;
结果将会显示符合条件的所有组别,及其成员信息。如果IS_MEMBER字段显示为Y,代表此用户是该组的成员。
官方英文解释
USER_JOINGROUPS
describes join groups belonging to the user. A join group is a user-created object that consists of two or more columns that can be meaningfully joined. The maximum number of columns that can be included in a join group is 255. The USER_JOINGROUPS
columns (except for JOINGROUP_OWNER
) are the same as those in DBA_JOINGROUPS
.
In certain queries, join groups enable the database to eliminate the performance overhead of decompressing and hashing column values. Join groups require an In-Memory column store (IM column store).
See Also:
-
“DBA_JOINGROUPS”
-
Oracle Database In-Memory
Guide for an introduction to join groups -
Oracle Database SQL
Language Reference for information about creating a join group using theCREATE INMEMORY JOIN GROUP
statement