NUM NUMBER Parameter number NAME VARCHAR2(80) Name of the parameter TYPE NUMBER Parameter type:

• 1 - Boolean

• 2 - String

• 3 - Integer

• 4 - Parameter file

• 5 - Reserved

• 6 - Big integer

VALUE VARCHAR2(4000) Parameter value for the session (if modified within the session); otherwise, the instance-wide parameter value DISPLAY_VALUE VARCHAR2(4000) Parameter value in a user-friendly format. For example, if theVALUE column shows the value262144 for a big integer parameter, then theDISPLAY_VALUE column will show the value256K. ISDEFAULT VARCHAR2(9) Indicates whether the parameter is set to the default value (TRUE) or the parameter value was specified in the parameter file (FALSE) ISSES_MODIFIABLE VARCHAR2(5) Indicates whether the parameter can be changed withALTER SESSION (TRUE) or not (FALSE) ISSYS_MODIFIABLE VARCHAR2(9) Indicates whether the parameter can be changed withALTER SYSTEMand when the change takes effect:

• IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.

• DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.（即不會對當前的會話產生影響，而對之後產生的會話有影響）

• FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.

ISINSTANCE_MODIFIABLE VARCHAR2(5) For parameters that can be changed withALTER SYSTEm, indicates whether the value of the parameter（不是指ISINSTANCE_MODIFIABLE這個檢視V$PARAMETER裡的欄位啊，而是就是指引數檔案裡的那些初始化引數，如db_name等） can be different for every instance (TRUE) or whether the parameter must have the same value for all Real Application Clusters instances (FALSE). If theISSYS_MODIFIABLE column isFALSE, then this column is alwaysFALSE. ISMODIFIED VARCHAR2(10) Indicates whether the parameter has been modified after instance startup:

• MODIFIED - Parameter has been modified with ALTER SESSION

• SYSTEM_MOD - Parameter has been modified with ALTER SYSTEM (which causes all the currently logged in sessions' values to be modified)

• FALSE - Parameter has not been modified after instance startup

註釋：ISMODIFIED為FALSE，說明該引數為非動態引數，不能動態修改（即例項執行期間修改該引數值）。不是說該引數不能靜態修改。任何引數都是可以靜態修改的，即alter SYSTEM\SESSION set 引數=引數值  scope=spfile；

ISADJUSTED VARCHAR2(5) Indicates whether Oracle adjusted the input value to a more suitable value (for example, the parameter value should be prime, but the user input a non-prime number, so Oracle adjusted the value to the next prime number) ISDEPRECATED VARCHAR2(5) Indicates whether the parameter has been deprecated (TRUE) or not (FALSE) ISBASIC VARCHAR2(5) Indicates whether the parameter is a basic parameter (TRUE) or not (FALSE) DESCRIPTION VARCHAR2(255) Description of the parameter UPDATE_COMMENT VARCHAR2(255) Comments associated with the most recent update HASH NUMBER

Hash value for the parameter name