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  • oracle database 12cr2 的 sys_context 函数

    sys_context虽然用的地方不多,但是十分强大,属于oracle的系统函数。归属于STANDARD 包

    SQL> select * from v$version ;
    
    BANNER                                           CON_ID
    -------------------------------------------------------------------------------- ----------
    Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production          0
    PL/SQL Release 12.2.0.1.0 - Production                            0
    CORE    12.2.0.1.0  Production                                0
    TNS for Linux: Version 12.2.0.1.0 - Production                        0
    NLSRTL Version 12.2.0.1.0 - Production                            0
    
    SQL> select * from v$database ;
    SQL> select * from v$thread ;
    SQL> select * from gv$instance ;

    查找 sys_context 的出处

    select *
    from dba_source vs
    where 1=1
    and upper(vs.text) like '%SYS_CONTEXT%'
    and vs.name = 'STANDARD'
    order by vs.line
    ;
    
    
    
      -- New built-in function SYS_CONTEXT
      function SYS_CONTEXT (namespace varchar2, attribute varchar2)
        return varchar2;
    
     -- SYS_CONTEXT now has an additional optional parameter
      function SYS_CONTEXT(namespace varchar2, attribute varchar2,
                           newoptional varchar2)
        return varchar2;   

    常用的几个

    select SYS_CONTEXT('USERENV','CURRENT_SCHEMA')
    from dual
    ;
    select SYS_CONTEXT('USERENV','SESSION_USER')
    from dual
    ;
    select SYS_CONTEXT('USERENV','CURRENT_USER')
    from dual
    ;
    select SYS_CONTEXT('USERENV','SID')
    from dual
    ;
    select SYS_CONTEXT('USERENV','CDB_NAME')
    from dual
    ;
    select SYS_CONTEXT('USERENV','CLIENT_IDENTIFIER')
    from dual
    ;
    select SYS_CONTEXT('USERENV','CLIENT_INFO')
    from dual
    ;
    select SYS_CONTEXT('USERENV','DATABASE_ROLE')
    from dual
    ;
    select SYS_CONTEXT('USERENV','DB_DOMAIN')
    from dual
    ;
    select SYS_CONTEXT('USERENV','DB_NAME')
    from dual
    ;
    select SYS_CONTEXT('USERENV','DB_UNIQUE_NAME')
    from dual
    ;
    select SYS_CONTEXT('USERENV','HOST')
    from dual
    ;
    select SYS_CONTEXT('USERENV','INSTANCE')
    from dual
    ;
    select SYS_CONTEXT('USERENV','INSTANCE_NAME')
    from dual
    ;
    select SYS_CONTEXT('USERENV','IP_ADDRESS')
    from dual
    ;
    select SYS_CONTEXT('USERENV','ISDBA')
    from dual
    ;
    select SYS_CONTEXT('USERENV','LANG')
    from dual
    ;

    参考:
    https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sqlrf/SYS_CONTEXT.html#GUID-B9934A5D-D97B-4E51-B01B-80C76A5BD086

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  • 原文地址:https://www.cnblogs.com/ctypyb2002/p/9793017.html
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