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Oracle 12C R2-新特性-SQLPLUS提供查看历史命令的功能

2021-04-09 23:57:21 阅读：199 来源： 互联网

标签：12C R2 show list SQLPLUS command SQL entry history

使用户能够从当前会话的历史记录列表中运行，编辑或删除先前使用的SQL * Plus，SQL或PL / SQL命令。可以使用SET HISTORY命令在当前SQL * Plus会话中启用或禁用HISTORY命令。

1 命令及功能

命令：HISTORY

功能：提供执行，编辑，删除之前命令的功能。

2 使用方法

默认HISTORY是没有打开的。

SQL> HIST 3 EDIT

SP2-1650: History is off, use "SET HIST[ORY] ON" to enable History.

2.1 打开HISTORY

注意：默认记录100条命令而不是命令行数。

SQL> set history on

2.2 查看状态

SQL> show hist;

history is ON and set to "2"

2.3 设置记录命令条数

SQL> set history 2;  --设置为2条记录

2.4 查看已记录的命令

SQL> hist

  1  show user

  2  select

     1

     from dual;

2.5 编辑之前的命令

SQL> hist

  1  select

     1

     from dual;

  2  show sga;

SQL> hist 1 edit

SQL> hist

  1  show sga;

  2  select

     sysdate

     from dual;

2.6 删除之前的命令

SQL> hist

  1  show sga;

  2  select

     sysdate

     from dual;

SQL> hist 2 del[ete]

SQL> hist

  1  show sga;

2.7 运行之前的命令

SQL> hist

  1  select

     1

     from dual;

  2  show sga;

SQL> hist 2 run

 

Total System Global Area 1308622848 bytes

Fixed Size	    8792440 bytes

Variable Size	  889194120 bytes

Database Buffers	  402653184 bytes

Redo Buffers	    7983104 bytes

标签：SQLPLUS 历史命令

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DBA笔试面试讲解

HISTORY

Syntax

HIST[ORY] [n RUN | EDIT | DEL[ETE]] | [CLEAR | LIST]

Enables users to run, edit, or delete previously used SQL*Plus, SQL, or PL/SQL commands from the history list in the current session. You can enable or disable the HISTORY command in the current SQL*Plus session by using the SET HISTORY command.

The HISTORY command enables you to:

List all entries in the command history list.

Run an entry in the command history list.

Edit an entry in the command history list.

Delete an entry from the command history list.

Clear all entries in the command history list.

Terms

HIST[ORY]

Lists all entries in the command history list.

Represents an entry in the command history list. An asterisk (*) indicates the last used command in the command history list.

RUN

Enables you to execute entry n from the command history list.

EDIT

Enables you to edit entry n in the command history list, using the default text editor. After you edit entry n in the command history list and save the changes, a new entry is created at the end of the list. When the number of entries in the command history list reaches the maximum limit, the oldest entry in the list will be cleared to accommodate the new entry.

DEL[ETE]

Enables you to delete entry n from the command history list. After you delete an entry from the history list, the list is reordered to reflect the most recent changes.

CLEAR

Enables you to clear all entries in the history list. Once cleared, the history list cannot be recovered.

LIST

Lists all entries in the history list. This is the same as using the HIST[ORY] command by itself.

Usage

You can use the SQL*Plus DEFINE command to define the variable, _EDITOR, to hold the name of your preferred text editor. For example, to define the editor used by EDIT to be vi, enter the following command:

DEFINE _EDITOR = vi

EDIT attempts to run the default operating system editor if _EDITOR is undefined. See the command for more information.

Example 12-1 Examples

The following example executes the fifth entry in the history list:

HIST[ORY] 5 RUN

The following example allows you to edit the third entry in the history list:

HIST[ORY] 3 EDIT

The following example allows you to delete the second entry from the history list:

HIST[ORY] 2 DEL[ETE]

The following example allows you to delete all entries from the history list:

HIST[ORY] CLEAR

The following example shows you how to enable or disable command history, and how to check the command history status:

SQL> set history on
SQL> show history
History is ON and set to "100"
SQL> set history off
SQL> show history
History is OFF
SQL> set history 1000
SQL> show history
History is ON and set to "1000"

The following example shows you how to list all entries in the history list:

SQL> show history
History is ON and set to "100"
SQL> show user
USER is "SYSTEM"
SQL> desc dual
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 PROD                                               VARCHAR2(1)

SQL> select * from dual;

D
-
X

SQL> history 4 run

D
-
X

SQL> history
  1  show history
  2  show user
  3  desc dual
* 4  select * from dual;

An asterisk (*) indicates the last used command in the command history list.

The following example shows you how to list all entries in the history list, and then execute the second entry:

SQL> history
  1  show history
  2  show user
  3  desc dual
* 4  select * from dual;
SQL> history 2 run
USER is "SYSTEM"
SQL> history
  1  show hist
* 2  show user
  3  desc dual
  4  select * from dual;

标签：12C,R2,show,list,SQLPLUS,command,SQL,entry,history
来源： https://blog.51cto.com/lhrbest/2695706

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