Oracle 9i SYS_CONTEXT函数的使用方法

        AUTHENTICATION_DATA
        Data being used to authenticate the login user. For X.503 certificate authenticated sessions, this field returns the context of the certificate in HEX2 format.
        Note: You can change the return value of the AUTHENTICATION_DATA attribute using the length parameter of the syntax. Values of up to 4000 are accepted. This is the only attribute of USERENV for which Oracle implements such a change.

        AUTHENTICATION_TYPE
        How the user was authenticated:
        DATABASE: username/password authentication
        OS: operating system external user authentication
        NETWORK: network protocol or ANO authentication
        PROXY: OCI proxy connection authentication
        BG_JOB_ID
        Job ID of the current session if it was established by an Oracle background process. Null if the session was not established by a background process.
        CLIENT_INFO
        Returns up to 64 bytes of user session information that can be stored by an application using the DBMS_APPLICATION_INFO package.

        CURRENT_SCHEMA
        Name of the default schema being used in the current schema. This value can be changed during the session with an ALTER SESSION SET CURRENT_SCHEMA statement.

        CURRENT_SCHEMAID
        Identifier of the default schema being used in the current session.

        CURRENT_USER
        The name of the user whose privilege the current session is under.

        CURRENT_USERID
        User ID of the user whose privilege the current session is under.

        DB_DOMAIN
        Domain of the database as specified in the DB_DOMAIN initialization parameter.

        DB_NAME
        Name of the database as specified in the DB_NAME initialization parameter.

        ENTRYID
        The available auditing entry identifier. You cannot use this option in distributed SQL statements. To use this keyword in USERENV, the initialization parameter AUDIT_TRAIL must be set to true.

        EXTERNAL_NAME
        External name of the database user. For SSL authenticated sessions using v.503 certificates, this field returns the distinguished name (DN) stored in the user certificate.

        FG_JOB_ID
        Job ID of the current session if it was established by a client foreground process. Null if the session was not established by a foreground process.

        HOST
        Name of the host machine from which the client has connected.