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 the CREATE INMEMORY JOIN GROUP statement


数据运维技术 » Oracle 视图 USER_JOINGROUPS 官方解释,作用,如何使用详细说明